Frank ICSE Chemistry Solutions

Frank ICSE Solutions for Class 9 Chemistry – Atmospheric Pollution

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Frank ICSE Solutions for Class 9 Chemistry – Atmospheric Pollution

PAGE NO :158
Solution 1:
Acid rain is the rain that has an excessive amount of acid in it than that of normal. Two air pollutants that cause acid rain are-

    1. Oxides of nitrogen
  1. Oxides of sulphur

Solution 2:
Acid rain is responsible for retarding forest’s growth and other vegetation. Acid rain makes the soil acidic and adversely affects the plants.

Solution 3:
70% of acid rain is due to sulphur dioxide. Oxides of sulphur and nitrogen released into atmosphere from number of sources.These oxides of nitrogen gets converted into nitrogen dioxide(NO2) which reacts with water to form nitric acid.Similarly, sulphur dioxide reacts with atmospheric oxygen to form sulphur trioxide which with water forms sulphuric acid.These come down on earth as acid rain.

Solution 4:
Acid rain can be reducd by-

  1. There should be reduction in fossil fuel combustion.
  2. Use of alternate cleaner energy sources should be encouraged. Eg-nuclear power, hydro power, wind energy, solar energy etc.
  3. Air filters and scrubbers are fitted in tall industrial chimneys to control air pollution.
  4. Catalytic converters in vehicle reduce nitrogen oxide emissions from automobiles.

Solution 5:

Acid rain cause extensive damage to the environment.

  1. Vegetation – The acid rain makes the soil acidic. This adversely affects the plants and animals. This damages leaves of plants and trees. This is responsible for retarding forests and other vegetation.
  2. Fertility of soil – The activity of symbiotic nitrogen fixing bacteria present in the nodules of leguminous family is inhibited. This is responsible for destroying or reducing the fertility of the soil.
  3. Water bodies – Acid rain renders the river, lakes or even ocean water acidic, there by adversely affecting marine animals. Changes in pH affect the reproduction and survival of many species of fish and other animals.
  4. Buildings and monuments – Acid rain cause extensive damage to the buildings and monuments made from marbles, limestone, slate and mortar.
    Frank ICSE Solutions for Class 9 Chemistry - Atmospheric Pollution 1
  5. Ecological balance – Acid rain is responsible for wiping out many bacterial and blue green algae, so disrupting the whole ecological balance.
  6. Human health – Acid rain has been found to be dangerous to human health. Acidic conditions can affect human nervous, respiratory and digestive systems.

Solution 6:
Air pollution is a harmful change in the natural air quality. It includes all physical, chemical and biological agents that modify the natural characteristics of the atmosphere.

Solution 7:
Ozone is an allotrope of oxygen. It has three oxygen atoms and its molecular formula is O3.It is an unstable blue gas having pungent odour found in troposphere. It is used as a powerful oxidant, bleach and water purifier.

Solution 8:
The gases causing ozone depletion are-

  1. Chlorofluoro carbons(CFCs or freons)
  2. Methane
  3. Nitrous oxides
  4. Carbon tetrachloride
  5. Methyl bromide(a soil fumigant and insecticide)
  6. Aircraft emission
  7. n-propyl bromide and Halon-1202

Solution 9:
Greenhouse gases are-

  1. Water vapour(H2O)
  2. Carbon dioxide(CO2)
  3. Methane(CH4)
  4. Oxides of nitrogen(NOx)

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Atmospheric Pollution 2

Solution 11:
Greenhouse effect means the progressive warming up of the earth’s surface due to the blanketing effect of man made carbon dioxide in the atmosphere. Greenhouse is a glasshouse with plants inside and  which allows short wave, incoming solar radiation to come in but does not allow the long wave,i.e. outgoing  infrared radiation to escape from inside the structure. Some of the gases in the earth’s atmosphere act like the glass in a greenhouse.They trap sun’s heat and keep the surface of the earth warm. Carbon dioxide and water vapour act as a greenhouse.

Solution 12:
Global warming is rise in the average global earth temperature . An increase in the average temperature of the earth’s atmosphere due to greenhouse effect  which can have far reaching effects on the climate and consequently on the key life, support systems of the planet, and this phenomenon is called global warming.

Solution 13:
Frank ICSE Solutions for Class 9 Chemistry - Atmospheric Pollution 3f

Solution 14:

  1. The warmer climate is changing the patterns of rainfall and snowfall.
  2. It causes increase in the frequency and severity of drought and flood also.
  3. It  is affecting our resources like water,forests  and different ecological systems.
  4. It also cause frequent natural disasters like cyclones, storms and hurricanes,floods and droughts.
  5. The global warming is damaging various ecosystems like mangrove-swamps , coral reefs and coastal lagoons, etc. due to various reasons like reduction in pH of oceanic water and increasing deposits of acids.
  6. It is damaging the world biodiversity. Vast varieties of birds, reptiles, insects, bacteria, fungi, rodents etc.have vanished out due to these effects.

Solution 15:
It has been found that in every southern spring(September-October) 50-95 %  of stratospheric ozone is destroyed at a height of 15-24 kms above ‘Antarctica’ creating pockets which have been described as ozone hole.

Solution 16:
The adverse effects of ozone layer depletion are-

  1. UV radiation causes sun-eye diseases (cataract), skin diseases, skin cancer and damage to immune system in our body.
  2. It damages plants and causes reduction in crop productivity.
  3. It damages embryos of fish, shrimps, crabs and amphibians.
  4. UV radiation damage fabrics, pipes, paints and other non-living materials on this earth.
  5. It contributes in the global warming. If the ozone depletion continues, the temperature around the world may rise at faster rate and to a large extent.

Solution 17:
Natural greenhouse effect is a process of thermal blanketing of the earth which maintains its temperature to sustain life on it. Without greenhouse effect, the climate of the earth would be too cold for most of the life to survive.

Solution 18:
The effect of warming and insulation of the earth caused due to some heat trapping gases accumulated in the atmosphere after their emission from the earth surface is called as greenhouse effect. Due to this there is rise in the average global earth temperature called global warming.

Solution 19:
When an ozone molecule is hit by UV wavelengths, it absorbs the radiant energy and photo dissociates into O2 and O giving off heat. Thus, keeps the UV radiation from reaching the earth’s surface and also causes a temperature inversion in the stratosphere that helps to maintain relatively stable climatic conditions on and near the ground.

Solution 20:
When an ozone molecule is hit by UV wavelengths, it absorbs the radiant energy and photo dissociates into O2 and O giving off heat. Thus, keeps the UV radiation from reaching the earth’s surface and also causes a temperature inversion in the stratosphere that helps to maintain relatively stable climatic conditions on and near the ground.

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Frank ICSE Solutions for Class 10 Chemistry – Metallurgy

by

Frank ICSE Solutions for Class 10 Chemistry – Metallurgy

PAGE NO : 152
Solution 9:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 1
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 2

Solution 10:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 3

Solution 11:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 4

Solution 12:

  1. Aqueous solution of sodium chloride is not used for electrolytic reduction of sodium metal because sodium metal formed at cathode after discharge of sodium ions( at cathode) will react with water to form alkali NaOH.
  2. For the reduction of a metal oxide a reducing agent other than carbon is carbon monoxide (CO).

 

Solution 13:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 5

PAGE NO : 169

Solution 1:

  1. Gold and Platinum.
  2. Charge.
  3. Gangue.
  4. Flux.
  5. Calcination.
  6. Roasting.
  7. Iron pyrites.
  8. Bauxite.
  9. Cryolite, aluminium fluoride, Calcium fluoride.
  10. Cathode: inner lining of gas-carbon of the electrolytic cell.
    Anode: Thick carbon rods dipping into the fused electrolytes.
  11. Thermite welding.
  12. Copper and silver.
  13. Aluminium, Iron.
  14. platinum and gold
  15. sodium and potassium

Solution 2:

  1. Zinc is used in galvanization and dry cells because zinc coating protects the iron from corrosion as it is more electropositive than iron hence it would be attacked first.
  2. Nitric acid can be stored in aluminium containers because it do not attack aluminium. It renders aluminium passive due to the formation of an oxide film on surface of aluminum.
  3. Aluminium oxide cannot be reduced by carbon because it is comparatively high in electrochemical series hence more reactive than carbon.
  4. A neutral gas other than oxygen is formed at the anode during electrolysis of fused alumina because the oxygen gas formed at the anode oxidizes the carbon of the anode to carbon dioxide.
  5. Extraction of aluminium was very difficult in the beginning because it was very expensive.
  6. Carbon anodes are used in the electrolytic extraction of aluminium because carbon in the form of graphite is a good conductor of electricity.
  7. Galvanized metal ions should not be used for storing food as food acids may react with the zinc coating and cause food poisoning.

Solution 3:

  1. Mineral: The naturally occurring compounds of metals which are generally mixed with earthy such as soil, sand, limestone and rocks are known as minerals.
  2. Ore: Those minerals from which a metal can be extracted profitably are called ores.
  3. Gangue: The rocky impurities like (SiO2) present in an ore are called gangue.
  4. Charge: The mixture of materials fed into a furnace to extract a metal is called charge.
  5. Flux: The substance added to get rid of gangue in the extraction of metal is called flux.
  6. Slag: The product obtained by the combination of gangue with flux is called slag.

PAGE NO : 170
Solution 4:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 6

Solution 5:

  1. Mercury.
  2. Silver.
  3. Zinc.
  4. Aluminium.

Solution 6:
As we know that minerals are the naturally occurring compounds of metals which are generally mixed with earthy such as soil, sand, limestone and rocks while ores are those minerals from which a metal can be extracted profitably.
Hence “All ores are minerals but all minerals are not ores”.

Solution 7:

  1. Iron: Haematite(Fe2O3) and Magnetite (Fe3O4).
  2. Zinc: Zinc blende (ZnS) and Calamine (ZnCO3).
  3. Aluminium:Bauxite(Al2O3) and Cryolite (AlF3.3NaF).

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 7

Solution 9:

Refining of metals: It is the further purification of metals obtained by reduction process to remove all the impurities.
Depending upon the nature of metal, nature of impurities and purpose for which metal is to be used. The three methods used for refining are:

  1. Liquation.
  2. Distillation.
  3. Electrolytic refining.

Solution 10:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 8

Solution 11:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 9

Solution 12:

Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 10

Solution 13:

Cryolite acts as a solvent for the electrolytic mixture in the electrolytic reduction of alumina in the Hall’s process.

Solution 14:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 11

Solution 15:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 12

Solution 16:
An alloy is a homogeneous mixture of two or more metals fused together and then solidified.
Alloys are made because they have many salient features:

  1. Tensile strength.
  2. Strength.
  3. Electrical hardness.

Solution 17:
The properties of alloys which are different from constituent metals are:

  1. Alloys are stronger and harder than the metals of which they are made.
  2. Alloys are more resistant to corrosion.

Solution 18:
Amalgam: A mixture or an alloy of mercury with a number of metals or non-metals is known as amalgams. An amalgam may be liquid such as Na/Hg or a solid like Zn/Hg.

  1. Iron does not form amalgam.
  2. Dental amalgam which is a mixture of mercury with a silver tin alloy is used for dental fillings.

Solution 19:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 13

Solution 20:

  1. Galvanization protects iron from rusting because in galvanization coating of zinc is done over iron articles and zinc being more electropositive would be attacked preferably than iron.
  2. Stainless steel is more useful than steel as it is harder, has high tensile strength, more lustre, more resistance to corrosion and many chemicals.
  3. Aluminium is extensively used for making aircraft parts because of features like high tensile strength, corrosion resistance light but hard and tough.
  4. Cold water has no action on aluminium while burning aluminium decomposes steam.

Solution 21:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 14

PAGE NO : 171
Solution 1991-1:

  1. Iron having a coating of zinc is called galvanized iron.
  2. iron which cannot be easily acted upon by acidsis called as passive iron. Galvanized iron is called passive iron since coating of zinc protects the iron from corrosion as zinc is more electropositive and so would be attacked first.

Solution 1991-2:
Zinc amalgam which is a mixture of zinc and mercury.

Solution 1992-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 15

Solution 1992-3:

  1. Nitrogen.
  2. Iodine
  3. Bromine
  4. Carbon in the form of graphite

Solution 1992-:

  1. Cryolite is Na3AlF6 and its chemical name is Sodium aluminium fluoride.
  2. Cryolite is used in the electrolysis of alumina. The function of cryolite is to
    • Reduce melting point of alumina
    • Make molten alumina a good conductor of electricity

Solution 1993-1:
Gold.

Solution 1993-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 16

Solution 1994-1:
Reactivity of metals with water Sodium, calcium, magnesium, iron

Solution 1994-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 17

Solution 1995-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 18

Solution 1995-2:
Zinc amalgam.

PAGE NO : 172
Solution 1996-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 19

Solution 1996-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 20

Solution 1996-3:
An alloy is a homogeneous mixture of two or more metals fused together and then solidified.

  1. The special property of duralumin is:
    • Light but hard
    • Resistant to corrosion
    • Ductile
  2. Type metal = Hard

Solution 1997-1:
Chromium and nickel is added to steel to make it stainless steel.

Solution 1997-2:
Ore: Those minerals from which a metal can be extracted profitably are called ores. For example bauxite ore is used to extract aluminium metal, hematite ore is used to extract iron metal.

Solution 1998-1:

  1. good, poor.
  2. non-malleable.
  3. form negative ions.
  4.  basic oxides.

Solution 1998-2:

  1. Mercury.
  2. Graphite.

Solution 1998-3:
Metals have 1, 2, 3 valence electrons while non-metals have 4, 5, 6 or 7 valence electrons.

Solution 1999-1:
Magnesium oxide, iron (II) oxide, lead (II) oxide and then copper (II) oxide.

Solution 1999-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 21

Solution 1999-3:

PAGE NO : 173
Solution 2000-1:

  1. Blue
  2. Red
  3. Hydrogen
  4. acidic, acidic
  5. graphite.

Solution 2001-1:

  1. Copper
  2. Iron
  3. Zinc
  4. Magnesium

Solution 2001-2:
Sodium > magnesium > Zinc > Iron > Copper

Solution 2002-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 22

Solution 2002-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 23

Solution 2003-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 24

Solution 2004-1:
Iodine is a non- metal that has a metallic luster and sublimes on heating.

Solution 2004-2:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 25

Solution 2004-3:
Zinc blende (ZnS)

Solution 2004-4:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 26

Solution 2004-5:
Galvanization.

Solution 2004-6:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 27

Solution 2005-1:

  1. (i) B, D F
    (ii) A, C E
  2. (i) Sodium hydroxide solution
    (ii) Cryolite
  3. Na3AlF6

PAGE NO : 175
Solution 2005-2:

  1. For stainless steel: iron, chromium
  2. For brass: Copper and zinc.

Solution 2006-1:

  1. Mercury.
  2. Cryolite.
  3. Roasting.
  4. Calcium silicate.
  5. Zone of heat absorption.

Solution 2007-1:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 28

Solution 2008-1:
(b)

PAGE NO : 176
Solution 2009-1:

  1. Carbon as it forms very large number of compounds while the rest do not.
  2. Mercury as it is a liquid metal while the rest aresolid.

Solution 2009-2:

  1. Copper reacts with concentrated nitric acid to produce nitrogen dioxide.
  2. Bauxite is the chief ore of aluminium.

Solution 2009-3:

  1. A is cathode and B is anode.
  2. Molten fluorides of Al, Na and Ba.
  3. Graphite rods.

Solution 2009-4:
Frank ICSE Solutions for Class 10 Chemistry - Metallurgy 29

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Frank ICSE Solutions for Class 10 Chemistry – Metals and Non-metals

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Frank ICSE Solutions for Class 10 Chemistry – Metals and Non-metals

PAGE NO : 151
Solution 1:
Frank ICSE Solutions for Class 10 Chemistry - Metals and Non-metals 1

Solution 2:
Frank ICSE Solutions for Class 10 Chemistry - Metals and Non-metals 2

Solution 3:
Metal which exist in liquid state is mercury.
Non-metal which exist in liquid state is bromine.
Concept Insight: Metals are usually solid while non-metals exist in all the three states.

Solution 4:
The most abundant metal in the earth’s crust is aluminium and the most abundant non-metal in the earth’s crust is oxygen.

Solution 5:

  1. Metals.
  2. Non-metals.
  3. Platinum and Gold.
  4. Potassium and Sodium.
  5. Potassium, Sodium and Calcium.
  6. Iron.
  7. Potassium and Sodium.
  8. Platinum.
  9. Platinum and Gold.
  10. Mercuric oxide (HgO) and Silver oxide (Ag2O).
  11. Potassium hydroxide (KOH) and Sodium hydroxide (NaOH).
  12. Potassium carbonate (K2CO3) and Sodium carbonate (Na2CO3).
  13. Potassium carbonate (K2CO3) and Sodium carbonate (Na2CO3).
  14. Potassium nitrate (KNO3) and Sodium nitrate (NaNO3).
  15. Mercuric nitrate (Hg(NO3)2) and silver nitrate (AgNO3)

Solution 6:
Frank ICSE Solutions for Class 10 Chemistry - Metals and Non-metals 3

Solution 7:

  1. Fe < Zn < Mg < Na.
  2. Na = Al < Cu<Fe
  3. Ca >Mg > Fe > Cu.

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Metals and Non-metals 4

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Frank ICSE Solutions for Class 10 Chemistry – Electrolysis

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Frank ICSE Solutions for Class 10 Chemistry – Electrolysis

PAGE NO : 131
Solution 1:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 1

Solution 2:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 2

Solution 3:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 3

Solution 4:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 4

Solution 5:
Three appilications of electrolysis are:

  1. Electro plating with metals
  2. Electrofining of metals
  3. Extraction of metals

Solution 6:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 6
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 7

Solution 7:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 8

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 9

Solution 9:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 10

PAGE NO : 132

Solution 10:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 11

Solution 11:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 12

Solution 12:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 13

Solution 13:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 14

Solution 14:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 15

Solution 15:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 16

Solution 16:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 17

Solution 17:
The main appilications of electrolysis are:

  1. Electro plating with metals
  2. Electrofining of metals
  3. Extraction of metals

Solution 18:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 18

Solution 19:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 19

Solution 20:

  1. Na2CO3
  2. NH3
  3. Graphite, Cu electrode
  4. NH4+
  5. Graphite

PAGE NO : 133
Solution 1994-1:

  1. The article to be plated must be made Cathode.
  2. The ions of the metal which is to be electroplated must be present in the electrolyte.
  3. The metal to be plated on the article must be made anode. It needs to be periodically replaced.

Solution 1994-2:
The passage of electricity through an electrolyte occurs through ions furnished by the electrolyte where as the passage of electricity through a copper wire occurs through electrons.

Solution 1995-1:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 20

Solution 1995-2:
It is the process of decomposition of an electrolyte in the molten or aqueous state by discharge of ions at the electrodes on the passage of an electric current.

Solution 1995-3:
Pure water does not conduct electricity because the degree of ionization is low. Thus to make it a good conductor of electricity acid is added to it which will increase the degree of ionization.

Solution 1996-1:
Substance which contain

  1. Ions only:- HCl
  2. Molecules only:- Petrol
  3. Both ions and molecules:- CH3COOH

Solution 1996-2:

  1. Electrolyte is a compound which either in aqueous solution or in molten state allows an electric current to pass through it and is accompanied by discharge of ions and finally into neutral atoms at the two electrodes.
  2. Non- electrolyte are substances which do not conduct electricity in fused or aqueous state. They contain only molecules and do not ionize. For example: petrol, alcohol.
  3. If the electrolyte is described as ‘strong electrolyte’ it means it completely dissociates into its constituting ions in aqueous solution.

Solution 1996-3:

  1. As for every copper ion discharged at the cathode, an ion of copper is formed at the anode which goes into the solution .Since atoms of copper are deposited at the cathode, the cathode becomesthicker and as the atoms of copper from the anode change into ions of copper, the anode becomes thinner.
  2. When platinum rods are used as electrodes, then x the blue colour of copper sulphate solution fades and sulphuric acid is formed. This is because oxygen is liberated at anode and copper metal is deposited at cathode
  3. Practical application of electrolysis of copper sulphate solution: This is the basis for purification of copper.
    Other metals like Zinc, Nickel, Silver .Lead can also be purified.

Solution 1997-1:
Lead Bromide should be in the molten state if it has to conduct electricity.

Solution 1997-2:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 21

Solution 1997-3:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 22

Solution 1998-1:

  1. Electrolyte
  2. Nickel
  3. Cathode
  4. Anode
  5. Cations

PAGE NO : 134
Solution 1999-1:
The electrolysis of lead bromide liberates lead at cathode and bromine at anode.

Solution 1999-2:
When a fused metallic chloride is electrolyzed, the metal is obtained at cathode.

Solution 2000-1:

  1. Strong electrolytes – dilute hydrochloric acid, dilute sulphuric acid, Ammonium chloride
  2. Weak electrolyte – Acetic acid, Ammonium hydroxide
  3. Non-electrolytes – Carbon tetrachloride

Solution 2002-3:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 23

Solution 2002-1:

  1. molecules.
  2. will not

Solution 2002-2:

  1. When sulphuric acid is added to water it becomes good conductor as addition of sulphuric acid causes dissociation of water molecules into H+ and OH– ions which are then responsible for conduction of electricity by pure water. The water thus obtained is called acidified water.
  2. Cathode, Anode

Solution 2003-1:
electricity, chemical

Solution 2004-2

  1. Molecules are found in a liquid compound which is a non-electrolyte.
  2. Non ionized molecules;
  3. H+ and X– particles will be present in dilute solution.
  4. Loss, Gain
  5. The ions of the metal which is to be electroplated on the article must be present in a solution.
  6. Redox reaction is one in which oxidation and reduction occurs simultaneously.
  7. Similarly in case of electrolysis:
    • At cathode: The cations gain electron and become neutral. As the electrons are gained the ion is said to be reduced.
    • At anode: The anions lose electron to form neutral atoms. As the electrons are lost the ion is said to be oxidized.
      Hence in electrolysis also the oxidation and reduction occurs hence it is an example of Redox reaction.

Solution 2004-1:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 24

PAGE NO : 135
Solution 2005-1:

  1. Copper metal is solid and has no mobile ions whereas an electrolyte should dissociate into oppositely charged ions to conduct the electric current.
  2. Hydrogen is released at the cathode when acidulated water is electrolyzed.
  3. In sodium chloride, Na+ and Cl– ions are not free to carry the electric current.
  4. (a) Reduced
    (b) Higher

Solution 2006-1:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 25

Solution 2006-2:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 26

Solution 2007-1:

  1. Molten ionic compound – Strong electrolyte
  2. Carbon tetrachloride- Non-electrolyte
  3. An aluminium wire- Metallic conductor
  4. A solution containing solvent molecules, solute molecules and ions formed by the dissociation of solute molecules- weak electrolyte
  5. A sugar solution with sugar molecules and water molecules- Non-electrolyte

Solution 2007-2:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 27

PAGE NO : 136
Solution 2008-1:
(d) Lead is deposited at the cathode

Solution 2008-2:
Frank ICSE Solutions for Class 10 Chemistry - Electrolysis 28

Solution 2009–2:
Mg (OH)2 as it is basic while rest are amphoteric.

Solution 2009–3:
Molten Lead bromide conducts electricity.

Solution 2009-4:

  1. Nickel ions move towards cathode.
  2. Nickel ions.

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Frank ICSE Solutions for Class 10 Chemistry – Mole Concept And Stoichiometry

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Frank ICSE Solutions for Class 10 Chemistry – Mole Concept And Stoichiometry

PAGE NO : 103
Solution 1:

  1. Gay-Lussac’s law: It states that ‘when gases react, they do so in volumes which bear a simple ratio to one another, and also to the volume of the gaseous product, provided all the volumes are measured at the same temperature and pressure’.
  2. Avogadro’s law : It states that ‘Under the same conditions of temperature and pressure, equal volumes of all gases contain the same number of molecules’.

Solution 2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 1

Solution 3:
When stating the volume of a gas, the pressure and temperature should also be given because the volume of a gas is highly susceptible to slight change in pressure and temperature of the gas.

Solution 4:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 2

Solution 5:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 3

Solution 6:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 4

Solution 7:

  1. Gram atom: “The quantity of the element which weighs equal to its gram atomic mass is called one gram atom of that element”.
    For example: The gram atomic mass of hydrogen is 1g. So, 1g of hydrogen is 1 gram atom of hydrogen.
  2. Gram mole: “A sample of substance with its mass equal to its gram molecular mass is called one gram molecule of this substance or one gram mole”.
    For example: Gram molecular mass of oxygen is 32 g. So One gram mole of oxygen is 32g.

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 5

Solution 9:
Empirical formula:“Empirical formula of a compound is the formula which gives the number of atoms of different elements present in one molecule of the compound, in the simplest numerical ratio”.
Molecular formula: “Molecular formula of a compound denotes the actual number of atoms of different elements present in one molecule of the compound”.

Solution 10:

  1. The empirical formula of C6H6 is: CH
  2. The empirical formula of C6H12O6 is: CH2O.
  3. The empirical formula of C2H2 is: CH
  4. The empirical formula of CH3COOH is: CH2O.

Solution 11:
Three pieces of information conveyed by the formula H2O is that:

  1. It shows that there are 2 hydrogen atoms and 1oxygen atoms present in H2O.
  2. The hydrogen and oxygen atoms are present in simplest whole number ratio of 2:1.
  3. It represents one molecule of compound water.

Solution 12:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 6

Solution 13:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 7

PAGE NO : 104

Solution 14:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 8

Solution 15:

  1. Na2SO4.10H2O.
  2. C6H12O6.

Solution 16:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 9

Solution 17:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 10

Solution 18:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 11

Solution 19:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 12

Solution 20:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 13

Solution 21:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 14

Solution 22:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 15

Solution 23:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 16

Solution 24:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 17

PAGE NO : 105
Solution 25:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 18

Solution 26:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 19

Solution 27:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 20

Solution 28:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 21

Solution 29:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 22

Solution 30:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 23

Solution 31:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 24

Solution 1996-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 25

Solution 1996-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 26

Solution 1996-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 27

Solution 1996-4:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 28

PAGE NO : 106
Solution 1997-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 29

Solution 1997-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 30

Solution 1997-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 31

Solution 1997-4:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 32

Solution 1998-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 33

Solution 1998-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 34

Solution 1999-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 35

PAGE NO : 107

Solution 1999-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 36

Solution 1999-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 37

Solution 2000-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 38

Solution 2000-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 39

Solution 2000-1:
Gay – Lussac proposed this law.

Solution 2001-2:
Molecular mass of ethane = 30
According to Gay-Lussac’s law:
2 vol. of C2H6 requires= 7 vol. of oxygen
Vol. of C2H6 = 2 vol. = 100 L
Vol. of oxygen required = 7 vol. =350 L

Solution 2001-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 40

PAGE NO : 108
Solution 2001-4:
The term is vapour density.

Solution 2001-5:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 41

Solution 2001-6:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 42

Solution 2001-7:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 43

Solution 2002-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 44

Solution 2002-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 45

Solution 2002-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 46

Solution 2003-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 47

Solution 2004-1:

Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 48

PAGE NO : 109
Solution 2004-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 49

Solution 2005-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 50

Solution 2006-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 51

Solution 2006-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 52

PAGE NO : 110
Solution 2006-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 53

Solution 2006-4:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 54

Solution 2007-1:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 55

Solution 2007-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 56

Solution 2008-1:
The gas laws which relates the volume of a gas to the number of molecules of the gas is avogadro’s law

PAGE NO : 111
Solution 2008-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 57

Solution 2008-3:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 58
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 59

Solution 2009-2:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 60

Solution 2009-3:
The correct statement is that equal volumes of all gases under identical conditions contain the same number of molecules.

Solution 2009-4:
Frank ICSE Solutions for Class 10 Chemistry - Mole Concept And Stoichiometry 61

Solution 2009-1:
The relative molecular mass of the gas is 10.

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Frank ICSE Solutions for Class 10 Chemistry – Analytical Chemistry

by

Frank ICSE Solutions for Class 10 Chemistry – Analytical Chemistry

PAGE NO : 75
Solution 1:

  1. Cuprous salts = Colourless
  2. Cupric salts = Blue
  3. Aluminium salts = Colourless
  4. Ferrous salts= Light green
  5. Ferric salts = Yellow
  6. Calcium salts = Colourless

Solution 2:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 1

Solution 3:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 2

Solution 4:
K2SO4.

Solution 5:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 3

Solution 6:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 4

Solution 7:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 5

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 6

Solution 9:
Examples of amphoteric hydroxides are: Zn(OH)2, Al(OH)3.

Solution 10:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 7

Solution 11:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 8

PAGE NO : 76
Solution 12:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 9

Solution 13:
The chloride of a metal which is soluble in excess of ammonium hydroxide is zinc chloride i.e. ZnCl2.

Solution 14:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 10

Solution 15:

  1. PbO
  2. Al2O3
  3. Na2ZnO2

Solution 16:

  1. transition, Cr3+, Fe2+, MnO44-.
  2. Zn(OH)2
  3. NH4Cl
  4. Al2O3, Al
  5. NH4OH

Solution 1992-1:

  1. Addition of KCN
  2. Addition of excess of NaOH.
  3. Addition of excess ofNH4OH

Solution 1993-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 11

PAGE NO : 77
Solution 1995-1:

  1. The metal ion present in solution A is Pb2+
    .
  2. The cation present in solution B is Cu2+. The probable colour of solution B is blue.

Solution 1996-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 12

Solution 1996-2:
 The solutions for the tests will be prepared by dissolving the given powders separately in water.

  1. Solution of Calcium carbonate:
    Calcium carbonate is CaCO3 and contains Ca2+ ions. Sodium hydroxide solution NaOH can be used to identify Ca2+ since its addition to calcium carbonate solution will give white precipitates of Ca(OH)2 which are sparingly soluble in excess of NaOH.
  1. Solution of Lead carbonate:
    Lead carbonate is PbCO3and contains Pb2+ ions. Ammonium hydroxide solution NH4OH can be used to identify Pb2+ since its addition to lead carbonate solution will give white precipitates of Pb(OH)2 which are insoluble in excess of NH4OH.
  2. Solution of Zinc carbonate:
    Zinc carbonate is ZnCO3 and contains Zn2+ ions. Sodium hydroxide solution NaOH can be used to identify Zn2+ since its addition to zinc carbonate solution will give white gelatinous precipitates of Zn(OH)3 which are soluble in excess of NaOH.

Solution 1996-3:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 13

Solution 1997-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 14

Solution 1998-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 15

Solution 1999-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 16

Solution 2000-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 17

PAGE NO : 78
Solution 2001-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 18

Solution 2003-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 19

Solution 2003-2:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 20

Solution 2004-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 21

PAGE NO : 79
Solution 2005-1:

  1. B and E (Iron (II) sulphate and Magnesium sulphate)
  2. C and F (Iron (III) chloride and Zinc chloride)
  3. D (Lead nitrate)
  4. A (Copper nitrate)
  5. F (Zinc chloride)

Solution 2006-1:
Frank ICSE Solutions for Class 10 Chemistry - Analytical Chemistry 22

Solution 2009-1:
C ( Aluminium oxide)

Solution 2009-2:

  1. P is Ferric chloride
  2. Q is an ammonium salt
  3. R is ferrous sulphate

Solution 2009-3:

  1. When BaCl2
  2.  solution is added to the given solution ZnSO4
  3. gives a white precipitate while no precipitate is obtained with ZnCl2 solution.
  4. When NaOH solution is added to the given solution, iron (II) chloride gives dirty green precipitate while reddish brown precipitate is obtained with iron(III) chloride.

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Frank ICSE Solutions for Class 9 Chemistry – Study of the First Element – Hydrogen

by

Frank ICSE Solutions for Class 9 Chemistry – Study of the First Element – Hydrogen

PAGE NO :146
Solution 1:

  1. (a) Symbol of hydrogen is ‘H’ and its molecular formula is H2.
  2. (b) 2 H means 2 atoms of hydrogen while H2 means one molecule of hydrogen.
  3. (c) Lavoisier gave “Hydrogen” its name because it means water product.

Solution 2:
Hydrogen is found in free state as well as in combined  state.

  1. In free state, it is found in traces in the earth’s crust and atmosphere. On the sun and bright stars, hydrogen is very abundant.It is suggested that the source of sun’s energy is fusion of hydrogen to helium.
  2. In combined state it is found in the compounds like water, acids, organic materials and minerals. Natural gas coming out from oil wells, coal mines and volcanoes invariably contains this gas.

Solution 3:
Hydrogen resembles the alkali in following manner-

  1. Electronic configuration – Hydrogen as well as alkali metals have one electron in their valence shell.
    H (1) = 1      ; Li(3)= 2, 1   ; Na(11) =2, 8, 1
  2. Ion formation – Hydrogen loses one electron to form H+ ion like the alkali metals which form Li+, Na+, K+ etc.
  3. Valency electrons – Like alkali metals, hydrogen exhibit valency of one in its compounds , as it has only one electron in its outermost shell.
  4. Combination with non-metals – Like alkali metals, hydrogen combines with non-metals such as oxygen, chlorine and sulphur forming their oxides, chlorides and sulphides respectively.
  5. Reducing action – Like alkali metals, hydrogen is also a very good reducing agent.

Solution 4:
Hydrogen resembles the alkali in following manner-

  1. Electronic configuration – All the halogens have seven electrons in their outermost shell and need just one more electron to attain stable inert gas configuration. Similarly, hydrogen with one electron in its outermost shell requires one electron to attain a stable inert gas(Helium) configuration.
  2. Valency – Hydrogen and halogen both show a valency of one.
  3. Non-metals – Hydrogen is non-metallic like halogen.
  4. Atomicity – Hydrogen as well as halogens are diatomic gases, e.g.H2,Cl2.Br2 etc.
  5. Ion formation – Halogens have a strong tendency to gain an electron to form halide ions.In similar way, hydrogen shows tendency to gain one electron to form hydride ion (H–).

Solution 5:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 1

Solution 6:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 2

Solution 7:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 3

Solution 8:
Hydrogen gas  obtained in the laboratory by dilute H2SO4 and granulated zinc have following impurities-

  1. Hydrogen sulphide (H2S),
  2. Sulphur dioxide (SO2),
  3. Oxides of nitrogen,
  4. Phosphine (PH3),
  5. Arsine (AsH3),
  6. Carbon dioxide, Nitrogen oxides,
  7. Water vapour
    They are removed by passing through-

    1. Lead nitrate solution-It absorbs H2S.
    2. Silver nitrate solution (AgNO3)-It absorbs PH3, AsH3
    3. Caustic potash (solid KOH)-It absorbs CO2, SO2, oxides of nitrogen
    4. Anhydrous calcium chloride or P2O5-It absorbs moisture.

Solution 9:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 4

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 5
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 6

PAGE NO :147
Solution 11:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 7

Solution 12:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 8

Solution 13:

  1. (a) Nickel, hydrogen
  2. (b) above, dilute mineral
  3. (c) covalent, electronegative
  4. (d) CuO, hydrogen, water
  5. (e) CO, H2
  6. (f) alkali
  7. (g) nascent hydrogen
  8. (h) water

Solution 14:

  1. (a) False
  2. (b) False
  3. (c) True
  4. (d) True
  5. (e) True
  6. (f) True
  7. (g) True
  8. (h) False

Solution 15:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 9
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 10

PAGE NO :148
Solution 16:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 11

Solution 17:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 12

Solution 18:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 14

Solution 19:
Some pieces of zinc granules are placed in Woulfe’s bottle and the apparatus is made in air tight. Now dilute sulphuric acid is poured through the thistle funnel.
Observation: The reaction takes place at room temperature even without heating. A brisk effervescence with the evolution of gas is seen inside the bottle.
If burning candle is brought near the bubbles of hydrogen gas, they explode.This proves that bubbles were full of hydrogen gas and they move up in the air because they are lighter than air.

Solution 20:

  1. (a) Meteorological balloons – The low density and high lifting power of hydrogen made it useful in meteorological balloons used for studying air currents and weather conditions. However, due to its highly inflammable nature it has been replaced by helium which has a lifting only slightly less than that of hydrogen.
  2. (b) In metallurgy – Hydrogen acts as a very good reducing agent. It is used to obtain metals by reducing their oxides.
  3. (c) In fuel – Hydrogen has very high heat of combustions, therefore it is used as fuel  in the form of coal gas, water gas and liquid hydrogen(for rocket propulsion).
  4. (d) In making fertilizers – A large quantity of hydrogen is used in the manufacture of ammonia by Haber process. Ammonia is used in manufacture of HCl and methyl alcohol.

Solution 21:
Frank ICSE Solutions for Class 9 Chemistry - Study of the First Element - Hydrogen 15

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Frank ICSE Solutions for Class 9 Chemistry – Atomic Structure

by

Frank ICSE Solutions for Class 9 Chemistry – Atomic Structure

PAGE NO :113
Solution 1:
Frank ICSE Solutions for Class 9 Chemistry - Atomic Structure 1

Solution 2:
Frank ICSE Solutions for Class 9 Chemistry - Atomic Structure 2

Solution 3:

  1. (a) Mass of an atom – Protons and neutrons
  2. (b) Size of an atom – Electrons

Solution 4:

Three fundamental particles of an atom are-

  1. Proton
  2. Electron
  3. Neutron

Solution 5:

  1. (a) An atom – An atom is the smallest particle of an element which may or may not be capable of independent existence.
  2. (b) An element – An element is usually defined as a pure substance that contains only one kind of particles. These particles may be atoms or molecules.

Solution 6:
Atomic number – The number of protons present in the nucleus of an atom is called the atomic number of the atom.
It is denoted by ‘Z’.

Solution 7:
The protons and neutrons are collectively called as nucleons.

Solution 8:
Isotopes are atoms of the same element, having the same atomic number, same chemical properties but different mass number, i.e., the atoms differ in the number of neutrons. The three isotopes of hydrogen atoms are-

  1. Protium
  2. Deuterium
  3. Tritium

Solution 9:
Electrons take part in a chemical reaction. Therefore, the chemical properties of an element depend upon the electronic configuration. Since, isotopes of an element have the same atomic number and hence same electronic configuration. So, they exhibit the same chemical properties.

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Atomic Structure 3

Solution 11:
The outermost orbit of an element is called valence shell. The electrons present in the outermost orbit (valence shell) of an element are called valence electrons.

Solution 12:
Atoms may have incomplete octet. During the formation of a molecule, an atom of a particular element gains, loses or shares electrons until it acquires a stable configuration of eight electrons in its valence shell.

Solution 13:

  1. (a) Atomic number = Number of protons = 20
  2. (b) Mass number = Number of protons +Number of electrons = 20 + 20 = 40
  3. (c) Electronic configuration = 2, 8, 8, 2
  4. (d) Valency = 2

Solution 14:

  1. (a) A=1
    B=3
    C=2
    D=1
    E=1
  2. (b) E contains the greatest number of neutrons.
  3. (c) A contains the least number of electrons.
  4. (d) B contains equal number of electrons and neutrons.
  5. (e) A is a metal.
  6. (f) Fluorine is the most reactive of the non-metals.
  7. (g) Both are electronegative and non-metals.
  8. (h) D and E belongs to a particular family.
  9. (i) A3B will be the formula if atoms of A combines with atoms of B.
  10. (j) ‘B’ will combine in  a trivalent  element while ‘C’ will combine as a bivalent element.

PAGE NO :114
Solution 15:
“During the formation of the molecule, an atom of a particular element gains, loses electrons or shares electrons until it acquires a stable configuration of eight electrons in its valence shell” i.e. until it acquires octet.

Solution 16:
K can accommodate maximum of 2 electrons.
L can accommodate maximum of 8 electrons.
M can accommodate maximum of 18 electrons.

Solution 17:
Cathode rays are formed at the negative electrode of the discharge tube experiment.

Solution 18:

  1. In K maximum number of 2 electrons can be accommodated.
  2. In L maximum number of 8 electrons can be accommodated.
  3. In M maximum number of 18 electrons can be accommodated.
  4. In N maximum number of 32 electrons can be accommodated.

Solution 19:
Frank ICSE Solutions for Class 9 Chemistry - Atomic Structure 4

Solution 20:
Electronic configuration of magnesium is -2, 8, 2. Since, it has 2 electrons in its valence shell, so its valency is 2.

Solution 21:
Number of electrons in Sodium = 11
Number of protons in sodium = 11
Number of neutrons in sodium = 12
Number of nucleons in sodium = 23

Solution 22:
Inert elements are the elements which have completely filled valence shell. Since, they are already stable and do not need more electrons, they do not combine with other atoms. So, they exist as monoatoms in molecule.

Solution 23:

  1. (a) Hydrogen
  2. (b) K shell.
  3. (c) Magnesium
  4. (d) Isotopes
  5. (e) Helium has zero valency.

Solution 24:

  1. (a) The number of protons = 9
  2. (b) The number of neutrons = 19 – 9 = 10
  3. (c) The number of electrons = 9

Solution 25:
Atomic number is the number of protons of an atom which is unique to an atom but mass number is the total of number of protons and number of neutrons which may or may not be same to other atoms since there is probability of combination of number of protons and number of neutrons be same for two atoms.

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Frank ICSE Solutions for Class 9 Chemistry – Water

by

Frank ICSE Solutions for Class 9 Chemistry – Water

PAGE NO :96
Solution 1:
The molecular formula of water is H2O, this shows that water is not an element but it is a compound made up of two elements hydrogen and oxygen  combined in a fixed ratio, i.e., 1:8 by mass. This also shows that the properties of water is totally different from those of hydrogen and oxygen as compounds have completely different properties than the elements of which it is made up of.

Solution 2:
Two characteristics properties responsible for making water a good solvent are:

  1. Water molecule can form hydrogen bonds with the molecules of other compounds.
  2. Water molecule is polar in nature.

Solution 3:
Frank ICSE Solutions for Class 9 Chemistry - Water 1

Solution 4:

  1. (a) Physical properties of water:
    1. Pure water is colourless, transparent, odourless and tasteless liquid.
    2. Boiling and Freezing points: At normal atmospheric pressure water boils at 100oC and freezes at 0oC.
    3. Pure water being a covalent compound is a very poor conductor of heat and electricity.On addition of electrolytes it becomes a good conductor of heat and electricity.
    4. Solvent properties:Water is a remarkable solvent dissolves many substances forming aqueous solutions because of its high dielectric constant.
    5. Anomalous behavior: On cooling water contracts in volume, as do other liquids, but at 4o C, it starts expanding, and continues to do till the temperature reaches 0oC,the point at which it converts to ice.
  2. (b)
    1. Boiling point of water: It increases with the addition of salt in water.
    2. Freezing point of water: It decreases with the addition of salt in water.
    3. Density of water: It increases with the addition of salt in water.

Solution 5:
Due to its high specific heat capacity, water is used in cooling systems for e.g., as coolant in motor car radiators.

Solution 6:
Frank ICSE Solutions for Class 9 Chemistry - Water 2

Solution 7:

  1. (a) Water reacts with metals oxides: corresponding hydroxides are formed which act as alkalis.
  2. (b) Water reacts with non metals oxides: corresponding acids are formed.

Solution 8:
Frank ICSE Solutions for Class 9 Chemistry - Water 3

Solution 9:
We can test the odourless, colourless liquid by:

  1. Measuring its boiling point, if comes out to be 100 oC then it confirms the liquid to be water.
  2. Measuring its melting point, if comes out to be 0 oC then it confirms the liquid to be water.

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Water 4

Solution 11:

  1. (a) Water being the universal solvent ,acts as an important mode of transport in plants,also water taken from natural source contains dissolved salts in them which is essential for the growth and development of plants
  2. (b) Water constitutes 3/4th of our human body and it is necessary for the survival of human beings and being the universal solvent helps in transportation and also regulates the body temperature.It also contains dissolved salts which supply essential minerals which are necessary for our body.

Solution 12:
Frank ICSE Solutions for Class 9 Chemistry - Water 5

Solution 13:
Frank ICSE Solutions for Class 9 Chemistry - Water 6

Solution 14:
Density of water is 0.997 gcm-3 at 4oC . The density of water decreases when the temperature increases above 4oC or decreases below 4oC.
At 40C, water has its maximum density and minimum volume. At any temperatur above or below 4 C, the density of water decreases. This property is called anomalous expansion of water. The significance of this unique property of water is that it enables marine life to exist in the colder regions of the world, because even when water freezes on the top, it is still liquid below the ice layer.

Solution 15:
At 40C, water has its maximum density and minimum volume. The property of anomalous expansion of water enables marine life to exist in the colder regions of the world because even when water freezes on the top, it is still liquid below the ice layer.

PAGE NO :97
Solution 16:
Frank ICSE Solutions for Class 9 Chemistry - Water 11

Solution 17:
Frank ICSE Solutions for Class 9 Chemistry - Water 7

Solution 18:

  1. (a) Liquids: alcohols, acids
  2. (b) Solids: Sugar, urea
  3. (c) Gases: Oxygen, carbon dioxide

Solution 19:
Rain water is the purest form of natural water.

Solution 20:

  1. (a) Solid in a liquid: Solubility decreases with rise in temperature in an exothermic process, for example, calcium sulphate(CaSO4), sodium sulphate(NaSO4), and in an endothermic reaction solubility increases with rise in temperature,for example potassium nitrte(KNO3) and sodium nitrate(NaNO3).
  2. (b) A gas in a liquid: Solubility decreases with rise in temperature.Thus, gases dissolves readily in cold water than in hot water.

Solution 21:
Frank ICSE Solutions for Class 9 Chemistry - Water 8

Solution 22:

  1. (a) Density of water is 0.997 gcm-3 at 4oC .The density of water decreases when the temperature decreases below 4oC. So ice has less density of 0.92 and is lighter  then that of water hence it floats on water.
  2. (b) A solution is said to be saturated if at a particular temperature if no more of the solute can be dissolved in it at that temperature, when the temperature is increased more solute particles can be dissolved in that saturated solution as the solubility of most of the substances generally increases with rise in temperature and thereby making it unsaturated.
  3. (c) Solubility of gases decreases with increase in temperature hence hot water contains less dissolved air than cold water.

Solution 23:

  1. (a) Solute: The substance which dissolves in a medium to produce a solution is called the solute.
  2. (b) Solvent: It is the medium in which the solute dissolves.
  3. (c) Solution: A homogeneous mixture that has a uniform composition throughout the volume of the mixture. It is the medium in which the solute dissolves.

Solution 24:

  1. (a) When we heat a saturated solution more solute can be dissolved in it, it as mostly solubility increases on raising the temperature and the solution then becomes an unsaturated solution.
  2. (b) When a hot saturated solution is cooled slowly and is kept undisturbed the excess salt does not separates out . Thus the solution becomes a supersaturated solution which contains more solute in it than it can hold at room temperature.
  3. (c) When the quantity of solvent increases,greater amount of solute can be dissolved.

Solution 25:
Frank ICSE Solutions for Class 9 Chemistry - Water 9

Solution 26:
Frank ICSE Solutions for Class 9 Chemistry - Water 10

Solution 27:
Solubility of a solid depends on:

  1. Size of particles: Smaller the size of particles of the solute, greater is the solubility.
  2. Contact between solute and the solvent: Increased contact between the solute and the solvent increases the solubility.
  3. Temperature: The variation of solubility with temperature depends on its nature i.e. whether the reaction is exothermic or endothermic.
    For exothermic reactions-The solubility decreases on increasing the temperature.
    For endothermic reaction-The solubility increases on increasing the temperature.

Solution 28:
Henry’s law states that:
At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

Solution 29:

  1. Z is least reactive so it will be found free in nature.
  2. X is more reactive so it will react with oxygen more readily and with ease.
  3. Z
  4.  Y is iron whose oxide is brown coloured Fe2O3.
  5. X
  6. The piece of Y i.e., iron is more reactive then copper so it will displace copper from copper nitrate and a brown layer of copper will be developed on the iron piece.

Solution 30:
Drop in, a crystal of the solute that is in the solution. If the crystal dissolves its unsaturated, if it stays the same size then its saturated and if it gets bigger than its supersaturated.

  1. This is because an unsaturated solution will be able to take in more solute, so it dissolves the crystal.
  2. A saturated solution will not take in more solute but will also not deposit any solute so the crystal stays the same size.
  3. A supersaturated solution wants to deposit its excess solute and become saturated, it just needs something to start it along.

The crystal starts it up and it will deposit its excess solute onto the crystal making the crystal bigger.

PAGE NO :98
Solution 31:

  1. (a) Increase in weight: when sodium chloride when exposed in air it gains moisture and its weight increases.
  2. (b) Decrease in weight: iron when exposed to air gets rusted due to the presence of moisture in the air it gets corroded, and hence its weight is reduced.
  3. (c) No effect on weight: when conc. Sulphuric acid when exposed to air  does not react and no change occurs in weight.

Solution 32:
Water pollution may be defined as the contamination of water by foreign substances which make it harmful for health of animals or plants or aquatic life, make it unfit for drinking and for domestic, industrial and agriculture use.

Solution 33:
Major pollutants of water are:
Ground water pollutants: Septic tanks, industry by products like pesticides, fertilizers, tanneries, mining wastes.
Surface water pollutants: No. of gases present in atmosphere like SO2, CO2, H2S, NOx, CO, etc., pollute surface water.
Lake water pollutant: organic wastes from hills, toxic effluents from urban areas, industrial effluents, dumping of huge amounts of sediments etc.,
River water pollutants: Industrial discharge, sewage discharges, detergents, discharges from drug, paper, and textile industries
Marine water pollutant: major pollutant is oil spills.

Solution 34:
Various sources of water pollution are:

  1. Natural process: Washing away of decomposed and animal wastes into main stream of water.
  2. Human activity: 
    1. (a)Discharge of Household detergents:  detergents used as a cleaning agent produce foam and pollute water. They do not undergo bio-degradation.
    2. (b) Discharge of industrial effluents: Industrial activities generate a variety of waste products which are generally discharged into water streams.The pollutants associated with the industrial effluents are  organic matter, inorganic dissolved salts, suspended solids. They inhibit oxidation or organic compounds; stabilize the colloidal impurities which do not aggregate to settle down.
    3. (c) Sewage:  Sewage is cloudy dilute aqueous solution containing minerals and organic matter.Sewage from homes and industries contains decomposable organic matter ,inorganic cations and anions,toxic metals etc.Pouring the drains and sewers in fresh water bodies causes water pollution.
      Water pollution due to sewage creates the following problems:

      1. Self purifying ability of water is lost and it becomes unfit for domestic purpose.
      2. Self regulatory capabilities of aquatic organism is retarded.
      3. Sewages produce pathogens which are diseases causing bacteria and result in water born gastro-intestinal diseases.

Solution 35:
Water treated for safe effluents involves sequential treatment:

  1. Primary treatment: The primary treatment involves physico-chemical processes to reduce settle able suspended solids of the wastes water and smoothened out individual effluent flow variations.It involves physic-chemical processes such as sedimentation,aeration,adsorption,oxidation etc.
  2. Secondary treatment: In this, the dissolved and colloidal organic matter present in waste is removed by biological processes involving bacteria and other micro organisms.
    These process may be aerobic or anaerobic.
    Aerobic treatment: Purification is carried out by aerobes in the presence of molecular oxygen.
    Anaerobic treatment: Purification of waste is achieved by anaerobes in complete absence of molecular oxygen.
  3. Tertiary treatment: It is the final treatment for polishing the effluents from secondary treatment. By this process suspended solids are removed, bacteria are removed, and organic and inorganic solids are removed.

Solution 36:
Two water born diseases are:

  1. Gastroenteritis
  2. Bacterial dysentery

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Frank ICSE Solutions for Class 9 Chemistry – Physical and chemical changes

by

Frank ICSE Solutions for Class 9 Chemistry – Physical and chemical changes

PAGE NO :74
Solution 1:
A physical change is a temporary change in which no new substance is formed and the composition or identity of the substance is not altered although certain specific physical properties may be changed.

Solution 2:
A chemical change is a permanent change in which the original substance gives rise to one or more substances with different properties.

Solution 3:
The reactions in which heat is evolved are called exothermic reactions while the reactions in which heat is absorbed are called endothermic reactions.

Solution 4:

  1. False
  2. False
  3. False
  4. False
  5. True

Solution 5:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 1

Solution 6:
Possible conditions for a chemical change are-

  1. One or more new substance is formed during reaction.
  2. The change occurring during the reaction is permanent.
  3. The mass of the substance undergoing a chemical change is generally altered.
  4. Chemical change involves  making and breaking of bond.

Solution 7:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 2

Solution 8:

(a) Redox reaction – The reaction in which both oxidation and reduction takes place simultaneously is known as rtedox reaction. Oxidation is a reaction that involves the addition of oxygen or the removal of the hydrogen. Reduction is a reaction that involves the addition of hydrogen or the removal of oxygen.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 3
(b) Oxidation – Oxidation is a reaction that involves the addition of oxygen or the removal of the hydrogen. In electronic concept, it is defined as the process in which an atom, molecule or ion loses one or more electrons. This results in increase in the positive charge or decrease in negative charge on the resulting species.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 4
(c) Reduction – Reduction is a reaction that involves the addition of hydrogen or the removal of oxygen. In the electronic concept, it is defined as the process in which an atom, molecule or ion gains one or more electrons. This results in increase in the negative  charge or decrease in positive charge on the resulting species.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 5

Solution 9:

  1. Exothermic reaction
  2. Endothermic reaction

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 6

Solution 11:
The chemical reactions which occur with the absorption of light energy are called photochemical reactions.
Examples-
Decomposition of silver nitrate takes place in the presence of light.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 7

Solution 12:
As the burning substance combines with oxygen ,the total mass of the products should be greater than that of the burning substance. For example,when,magnesium is burnt,a new substance magnesium oxide is formed,whose weight is greater than that of the original magnesium.
Experiment – A crucible is weighed containing about 0.5 gm of magnesium.Now crucible is heated.When magnesium begins to burn,the lid is put back on the crucible and the lid is occasionally raised to allow air to enter and burn the magnesium such that no product is lost.When,all the magnesium has been burnt up, the crucible is allowed to cool and then on weighing it  we observe that there is gain in weight.

Solution 13:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 8

Solution 14:
Three conditions necessary for burning are-

  1. The substance to be burnt must be combustible.
  2. A supporter of combustion such as air or oxygen must be present.
  3. A combustible substance must be heated to its ignition temperature.

PAGE NO :75
Solution 15:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 9

Solution 16:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 10

Solution 17:
When oxidation occurs there is a loss of electrons but simultaneously there is a gain of electrons by other species which is called reduction. These both process occur simultaneously so we can say that both oxidation and reduction go hand in hand and such reactions are known as redox reaction.

Solution 18:

  1. Copper is oxidized to copper sulphate while sulphur in sulphuric acid is reduced to sulphur dioxide.
  2. Silver in silver oxide is reduced to silver while oxygen in hydrogen peroxide is oxidised to molecular oxygen.

Solution 19:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 11
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 12

Solution 20:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 13

Solution 21:
A candle is a stick of paraffin wax with cotton wick.As a candle burns wax melts and trickles down. It gets solidified shortly. This is physical change. Paraffin wax is a mixture of hydrocarbons. When wick catches fire, paraffin wax melts, evaporates and burns in air like any hydrocarbon to give carbon dioxide and water. This is a chemical change.

Solution 22:

  1. physical
  2. chemical
  3. chemical
  4. physical

Solution 23:
Two examples are:-

  1. Burning of wood-carbon get oxidized and oxygen gets reduced.
  2. Rusting-In it iron is oxidized.

Solution 24:

  1. Chromium(VI) .
  2. Hydrogen peroxide
  3. Barium carbonate.
  4. Silver nitrate.
  5. Manganese dioxide.

Solution 25:
Ignition temperature – Ignition temperature is the lowest temperature up to which temperature of a substance must be raised so that it catches fire.
A combustible substance must be heated to its ignition temperature for burning.

Solution 26:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 14

Solution 27:
On heating few crystals of iodine in a test tube, the grey crystals sublimes and dense violet fumes are seen. On cooling, the vapours again form the crystals. So, a physical change can be reversed.

Solution 28:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 20

Solution 29:
When water is freezed and evaporated, these both are physical changes because-

  1. The change is temporary and reversible.
  2. No new substance is formed and the chemical composition of the original substance remains the same.
  3. Mass of the substance remains unchanged
  4. The amount of energy required to bring about a physical change is generally equal to the amount of energy required to reverse the change. Hence,there is no net energy change involved.

Solution 30:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 15

Solution 31:
Air is necessary for burning. Incorrect amount of air in fuel combustion accounts for the largest losses in combustion system. If the fuel does not get enough air for combustion it will generate smoke and a potentially unhealthy mixture of gas products.

Solution 32:

  1. (a) Combustible substances -The substances that catch fire and burn easily. Ex-Wood, Charcoal, petrol, kerosene etc.
    Non-combustible substances-Substance which cannot burn in air or oxygen are called as non- combustible substances. Ex-Nitrogen gas, carbon dioxide etc.
  2. (b) Two substances other than oxygen that support combustion are-
    1. Hydrogen
    2. Nitrogen

Solution 33:

  1. (a)
    1. Burning of coal in air releases CO2 in air.
    2. Respiration releases carbon dioxide and water vapours.
  2. (b)
    1. Photosynthesis removes CO2 from the atmosphere. Plants take carbon dioxide from the atmosphere in the presence of sunlight and use it to synthesise glucose with the liberation of oxygen.
    2. Some man made chemical activities such as setting of mortar also use atmospheric carbon dioxide and helps in removing carbon dioxide.

Solution 34:
Nitrogen is inert in nature and does not support combustion while oxygen supports combustion.If proportions of nitrogen and oxygen in the air were reversed then the rate of combustion of substances will increase.

Solution 35:
Heating of sulphur – If some powdered sulphur is heated gently in a glass test tube, it melts to a pale yellow liquid. Flame is removed to stop heating, it is quickly changed back to solid sulphur.

PAGE NO :76
Solution 36:
Activity series – The arrangement of the metals in the decreasing order of their chemical reactivity is called the activity series.
In displacement reactions, a more reactive element (metal or non-metal) displaces a lesser reactive element from its compound. With the help of the activity series, it is possible to predict which metals will displace other metals from their solutions.

Solution 37:
Balance of oxygen and carbon dioxide is maintained in nature because there is a natural oxygen cycle and a natural carbon cycle operating all the time by which the desired proportions of the two gases in the air are maintained. This is also known as carbon dioxide-oxygen cycle.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 16

Solution 38:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 17

Solution 39:
Carbon dioxide from the atmosphere enters the plant through photosynthesis, where carbohydrates are produced. From green plants, the carbon in the form of carbohydrates, etc. enter the animal and human bodies. The atmospheric carbon dioxide gets dissolved in oceans by diffusion. Marine algae and photosynthetic bacteria obtain carbon dioxide from water.
Carbon dioxide returns to the atmosphere by respiration, combustion of fossil fuels like coal, wood, petroleum etc., weathering of rocks, volcanic eruptions etc.
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 18

Solution 40:
Frank ICSE Solutions for Class 9 Chemistry - Physical and chemical changes 18

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Frank ICSE Solutions for Class 10 Chemistry – Study Of Acids, Bases and Salts

by

Frank ICSE Solutions for Class 10 Chemistry – Study Of Acids, Bases and Salts

PAGE NO : 62
Solution 1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 1

Solution 2:

  1. (i) Hydrogen chloride HCl
    (ii) Nitric acid HNO3
  2. (i) Carbonic acid H2CO3
    (ii) Oxalic acid (COOH)2
  3. (i) Sulphuric acid H2SO4
    (ii) Hydrogen chloride HCl
  4. (i) Carbonic acid H2CO3
    (ii) Acetic acid

Solution 3:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 2

Solution 4:

  1. The pH of a solution is defined as the negative logarithm (base 10) of the hydronium ion concentration present in the solution.
    pH =-log10 [H3O+]
  2. The three applications of pH scale are:
    • It is used to determine the acidic or basic nature of the solution.
    • It is used to determine hydronium ion concentration present in the solution.
    • It is used to find out neutrality of the solution.

Solution 5:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 3

Solution 6:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 4

Solution 7:

  1. Base in solution furnishes the ions:
    Hydroxide ion/ oxide ion and a metallic ion.
  2. A weak alkali furnishes the ions:
    Hydroxide ion and metallic ion and molecules of weak alkali./
  3. An acid in a solution furnishes the ions:
    Hydronium / Hydrogen ion and a negative ion.

Solution 8:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 5

PAGE NO : 63
Solution 9:

  1. CaO
  2. NaOH
  3. CuO
  4. Cu[(OH)2]
  5. H2CO3
  6. Ferric hydroxide [Fe (OH)3].
  7. CuO
  8. NH3

Solution 10:
Anhydrous hydrogen chloride is not an acid but its aqueous solution is a strong acid because anhydrous means without water and we know that the property of acidity is shown by a substance only when it is dissolved in water or its aqueous solution is prepared.

Solution 11:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 6

Solution 12:
Strength of an acid measures the ease with which the acid can ionize to produce hydrogen or hydronium ions when dissolved in water. Those acids which can easily ionize to form hydrogen ions are called strong acids while those which can partially ionize to form hydrogen ions are called weak acids.
Strength of an acid depends upon many factors such as:

  1. Molecular structure of the acid
  2. The temperature
  3. Properties of the solvent

Solution 13:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 7

Solution 14:
Solution B with pH value 9 will give pink colour with phenolphthalein.
Concept Insight: Bases give pink colour with phenolphthalein because a base will abstract two protons from phenolphthalein and the resulting phenolphthalein ion provides pink colour to the solution.

Solution 15:
Two indicators for identification of acid are methyl red and Thymol blue.

Solution 16:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 8

Solution 17:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 9

Solution 18:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 10

Solution 19:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 11

Solution 20:

  1. Efflorescence: It is the phenomenon by which hydrated salts on exposure to dry air, lose their water of crystallization and crumble to powder.
  2. Hygroscopy: It is the phenomenon by which substances absorb moisture from air, but only sufficiently so as to become wet.
  3. Water of crystallization: It is the fixed amount of water that is present in a crystal as an integral part of its constitution. Hydrated salts are salts having water of crystallisation.

Solution 21:
Deliquescence is the phenomenon by which certain salts absorb moisture from air, lose their water of crystallization and dissolve in it to form a saturated solution.
The substances which exhibit deliquescence are called deliquescent.
For example Caustic soda NaOH, Caustic potash KOH.

Solution 22:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 12

Solution 23:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 13

Solution 24:

  1. Common salt gets wet during rainy season because the commercially available salt contains impurities, like magnesium chloride, which are deliquescent substances. These absorb moisture from atmosphere and make the table salt wet.
  2. (i)  Na2CO4.10H2O = Washing soda
    (ii) MgSO4.7H2O = Epsom salt
    (iii)CuSO4.5H2O = Blue vitriol
    (iv) ZnSO4.7H2O = White vitriol

PAGE NO : 64
Solution 1996-1:

  1. pH of a solution having pH 7 can be increased by adding a base to it such as NaOH.
  2. pH can be decreased by adding an acid such as HCl to it.
    If a solution changes colour of litmus from red to blue, it shows that its pH is above 7.

Solution 1996-2:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 14

Solution 1996-3:

  1. Zinc sulphate = Zinc and dilute sulphuric acid
  2. Copper sulphate = Copper oxide and dilute sulphuric acid
  3. Sodium sulphate = Sodium carbonate solution and dilute sulphuric acid
  4. Lead sulphate = Lead carbonate and dilute sulphuric acid

Solution 1997-1:
The term acid salt means the salt formed by partial replacement of the hydrogens present in the acid by metallic or ammonium ions.
For example: NaHCO3

Solution 1997-2

  1. pH scale is used to express the acidic or basic nature of solution.
  2. pH of pure water is 7 since it does not have any impurities.
  3. (a) A soluble oxide of A will have pH less than the pH of pure water i.e. below 7.
    (b) A solution of ‘B’ will have more pH than pure water i.e. above 7.

Solution 1997-3:

  1. Water of crystallization: It is the fixed amount of water that is present in a crystal as an integral pat of its constitution. Compounds having water of crystallization are called hydrous salts.
    For example: Sodium carbonate Na2CO3 has 10 molecules of water present as water of crystallization Na2CO3.10H2O
  2. Anhydrous: Hydrous salt on heating lose their water of crystallization, such salts are then called anhydrous.
    For example:Na2CO3.10H2O on losing 10 molecules of water forms Na2CO3

Solution 1997-4:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 15

Solution 1998-1:

  1. Water of cystallization.
  2. White.
  3. Efflorescence.
  4. Sodium chloride.

Solution 1998-2:
Those acids which ionize partially in aqueous solution and thus they contain ions as well as molecules of the acid. Organic acid such as CH3COOH, is a weak acid.

Solution 1998-3:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 16

PAGE NO : 65
Solution 1998-4:
The name and formula of the acid salt which gives sodium ions and sulphate ions in solution is Sodium hydrogen sulphate NaHSO4

Solution 1999-1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 17

Solution 2000-1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 18

Solution 2001-1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 19

PAGE NO : 66
Solution 2002-1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 20

Solution 2003-1:

  1. Hydronium, positive.
  2. Acid, metal.

Solution 2003-2:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 21

Solution 2004-1:
methods for preparation:

  1. Preparation of copper(II) chloride.
    Action of an acid on an oxide or carbonate
  2. Preparation of iron(III) chloride.
    Direct combination
  3. Preparation of iron (II) chloride.
    Action of an acid on a metal
  4. Preparation of lead (ii) chloride
    Precipitation (double decomposition)
  5. Preparation of sodium chloride
    Neutralization of an alkali by an acid.

Solution 2005-1:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 22

PAGE NO : 67
Solution 2005-2:
Positive, hydroxyl, Salt, Neutralization.

Solution 2005-3:
When neutral litmus solution is added to sodium hydrogen carbonate solution, litmus solution turns red

Solution 2006-1:

  1. From pink to colourless.
  2. From orange to pink.
  3. From colourless to red.

Solution 2007-1:

  1. Hydronium
  2. Hydroxide
  3. Salt
  4. Water
  5. Hydrogen

Solution 2007-2:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 23

Solution 2008-1:

  1. Complex salt.
  2. Alkali.

Solution 2009-1:
Acidified potassium dichromate paper

PAGE NO : 68
Solution 2009-2:

  1. Solution B.
  2. Solution A.
  3. Solution B
  4. Solution of ammonium hydroxide NH4OH is a weak alkali.

Solution 2009-3:
Frank ICSE Solutions for Class 10 Chemistry - Study Of Acids, Bases and Salts 24

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Frank ICSE Solutions for Class 9 Chemistry – The Language of Chemistry

by

Frank ICSE Solutions for Class 9 Chemistry – The Language of Chemistry

PAGE NO :56
Solution 1:
Symbol – It is the short form or abbreviation used for the name of an element. It represents one atom of that element.
Formula – Formula of a compound represents the composition of a molecule of the substance in terms of the symbols of the elements present in the molecule.

Solution 2:

  1. CaCO3
  2. MgSO4
  3. Fe2 (SO4)3
  4. CaHCO3
  5. CuI
  6. K2Cr2O7
  7. KMnO4
  8. Na2SO4
  9. Mg (NO3)2
  10. Ca3 (PO4)2

Solution 3:

  1. Valency – The combining capacity of an element is called its valency.
  2. Helium < Sodium < Magnesium < Carbon < Phosphorous

Solution 4:
Law of conservation of matter governs a completely balanced equation. It states that “matter can neither be created nor destroyed.”

Solution 5:
A symbol signifies one atom of that element.

Solution 6:
Latin names of the following compounds are-
Iron                      –   Ferrum
Tin                        –   Stannum
Lead                     –   Plumbum
Sodium                –   Natrium
Potassium           –   Kalium
Mercury              –   Hydragyrum

Solution 7:
The equation in which the total number of atoms of each element in the reactants, on the left side of the equation is same as the number of atoms in the products formed, on the right side of the equation is called as balanced chemical equation.

Solution 8:
Frank ICSE Solutions for Class 9 Chemistry - The Language of Chemistry 1

Solution 9:
A chemical equation gives information about-

  1. What substances enter into a given reaction (reactants) and what products are formed as a result of the reaction.
  2. The  quantities of the reactants and the product formed.
  3. The  optimum conditions of temperature and pressure.

Solution 10:
Frank ICSE Solutions for Class 9 Chemistry - The Language of Chemistry 2

Solution 11:
H2 means hydrogen, O4 means oxygen and S means sulphur  in the formula of H2SO4.

Solution 12:

  1. The highest valency of the element Z is six.
  2. The formula of the fluoride of Z will be ZF6.

Solution 13:
The three valencies of element are-

  1. Two-Since the element X combines with two hydrogen to form H2X and two atoms of X combines with one carbon to form CX2.
  2. Four-Since the element X combines with two oxygen to form XO2.
  3. Six-Since the element X combines with three oxygen to form XO3.

Solution 14:
Variable valency – Some elements are capable of showing more than one valency in their compounds called variable valency.
Some elements show variable valency i.e. more than one valency since these elements have more than one common valency state.

Solution 15:
Chemical formula – It represents the composition of a molecule of the substance in terms of the symbols of the elements present in the molecule. The rule for writing the formula is criss-cross method.

  1. The positive and negative radicals are represented by their symbols and written side by side with the correct valency written below each.
  2. The valencies are divided by their highest common factor if any to get the simplest ratio.
  3. These numbers are then interchanged and written as subscripts.

Solution 16:
Frank ICSE Solutions for Class 9 Chemistry - The Language of Chemistry 3

Solution 17:

  1. Sodium hydrogencarbonate
  2. Sodium hexacyanoferrate(III)
  3. Manganese(II) borate
  4. Calcium phosphate
  5. Potassium manganate(VI)

Solution 18:
Co stands for cobalt which is an element while CO stands for carbon monoxide which is a compound.

Solution 19:
Radical – A radical is an atom or a group of atoms of same or different elements that behaves in the manner of positive or negative ion. Radicals have their own combining power(valency) and chemical formulae.
Examples-
Monovalent  radicals -H–,OH–,Cl–,NO3–,H+,Na+,K+,NH4+
Trivalent radicals-PO43- ,Fe(CN)63-,AsO3 3-,N3-,Fe3+,Al3+,Bi3+,Au3+

Solution 20:
Frank ICSE Solutions for Class 9 Chemistry - The Language of Chemistry 4

Solution 21:

  1. Anion – Negatively charged radicals are termed as anions.
  2. Cation – Positively charged radicals are termed as cations.

Solution 22:
Disadvantages associated with hit and trial method of balancing of equations-

  1. It is tedious and takes a long time.
  2. The method is rather difficult for balancing such equations which contain the same element being repeated in a number of compounds.
  3. It does not give any information regarding the mechanism of the reaction.

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