ICSE Class 10 Chemistry Sample Question Paper 3 with Answers

ICSE Class 10 Chemistry Sample Question Paper 3 with Answers

Maximum Marks: 40
Time: 1 1/2 Hours

Section-A [10 Marks]
(Attempt all questions from this Section)

Question 1.
Choose the correct answers to the following questions from the given options. (Do not copy the question, write the correct answer only.)
(i) The general formula of alkynes is:
(a) C_nH_2n-2
(b) C_nH_2n+2
(c) C_nH₂
(d) C_nH_2n+2O
Answer:
(a) C_nH_2n-2
Explanation:
The general formula of alkyne is C_nH_2n-2

(ii) The drying agent used to dry NH₃ is :
(a) P₂O₅
(b) Cone. H₂SO₄
(c) CaCl₂
(d) CaO
Answer:
(d) CaO
Explanation:
The drying agent used to dry NH₃ is quicklime (CaO).

(iii) The main ore used for the extraction of aluminium is:
(a) Calamine
(b) Bauxite
(c) Haematite
(d) Chalcopyrite
Answer:
(b) Bauxite
Explanation:
The main ore used for the extraction of aluminium is bauxite and Hall – Heroult process is the major industrial process for extraction of aluminium from its oxide alumina.

(iv) Formation of ethylene bromide from ethene and bromine is an example of:
(a) Hydrogenation reaction
(b) Dehydrohalogenation reaction
(c) Substitution reaction
(d) Addition reaction
Answer:
(d) Addition reaction
Explanation:
The reaction of ethene with Br2 to form 1,2-Dibromoethane (Ethylene bromide) is an addition reaction. The atoms that add to the double bond are located on adjacent carbon atoms, a common characteristic of addition reactions of alkenes.

(v) The delivery tube used in the laboratory preparation of hydrogen chloride is dipped in:
(a) Concentrated nitric acid
(b) Dilute nitric acid
(c) Concentrated sulphuric acid
(d) Dilute sulphuric acid
Answer:
(c) Concentrated sulphuric acid
Explanation:
The delivery tube is dipped in concentrated sulphuric acid so that easy movement of HCl gas takes place and no impurity can add to it. It also helps in making the HCl gas moisture-free.

(vi) When sulphuric acid is added to sodium carbonate brisk effervesence is produced which is due to:
(a) evolution of H₂S gas
(b) evolution of Cl₂ gas
(c) evolution of CO₂ gas
(d) evolution of O₂ gas
Answer:
(c) evolution of C02 gas
Explanation:
The reaction of sulphuric acid and sodium carbonate produces sodium sulphate, water, and brisk effervescence of carbon dioxide. The reaction is given as:
Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂ (↑)

(vii) The reactants for laboratory preparation of nitric acid are:
(a) Ammonium hydroxide and sulphuric acid
(b) Sodium nitrate and sulphuric acid
(c) Sodium nitrate and water
(d) Ammonium nitrate and water
Answer:
(b) Sodium nitrate and sulphuric acid
Explanation:
Nitric acid in the laboratory is prepared by reaction of sodium or potassium nitrate and sulphuric acid. They are distilled to produce the required ammonia.

(viii) The process used to convert impure alumina to pure alumina is:
(a) Roasting
(b) Electrolytic refining
(c) Purification
(d) Bayer’s process
Answer:
(d) Bayer’s process
Explanation:
Concentration of ore or purification of ore, i.e., conversion of bauxite (impure alumina) to pure alumina, is known as Bayer’s process. Roasting refers to the heating of compounds in the presence of air, while electrolytic refining is the process of purification of metal using electrolysis.

(ix) Calcium oxide reacts with HCl gas to produce __________ and water.
(a) Calcium chloride
(b) Calcium sulphate
(c) Hydrogen gas
(d) Chlorine gas
Answer:
(a) Calcium chloride
Explanation:
The reaction of calcium chloride with water is neutralisation and a double displacement reaction, which produces salt and water. The chlorine atom of HCl displaces oxygen from CaO and hence produces calcium chloride (CaCl₂).

(x) The compound A and B, as shown in the figure below, can be:

(a) Water and salt solution
(b) Water and cone. H₂SO₄
(c) Baking soda solution and water
(d) Water and NaOH solution
Answer:
(b) Water and cone. H₂SO₄
Explanation:
When water is added to concentrated sulphuric acid, a highly exothermic reaction occurs, leading to the spurting of the acid. This can be very dangerous.

Section-B [30 Marks]
(Attempt any three questions from this Section)

Question 2.
(i) Define:
(a) Homologous series
(b) Gangue or Matrix
(ii) Name the compound formed when:
(a) Ethene reacts with hydrogen chloride.
(b) Sodium aluminate is diluted with water and cooled to 50°C
(iii) Draw the structural diagram of the following isomers:
(a) Pentane
(b) 2-Methyl butane
(c) 2,2-Dimethyl propane
(iv) Complete and balance the following chemical equations:

Answer:
(i) (a) A series of compounds of the same family in which each member differ from its adjacent member by one CH₂ unit is called homologous series.
(b) The unwanted impurities which are associated with ore are called gangue or matrix, e.g., stone, clay etc.

(ii) (a) Ethyl chloride (chloroethane) is formed. The reaction can be represented as follows:

(b) Aluminium hydroxide is formed. The reaction can be represented as follows:
NaAlO₂ + 2H₂O → NaOH + Al(OH)₃↓

Question 3.
(i) Dry ammonia gas is passed over black substance as shown in figure below:

(a) Name the black substance A.
(b) Name the gas evolved B.
(c) Write a balanced equation for the reaction of ammonia with A.
(ii) State the following:
(a) The catalysts used in contact process.
(b) The product formed when glass rod dipped in NH₄OH is brought near the mouth of a bottle full of HCl gas.
(iii) State the observation for the following, when:
(a) Concentrated sulphuric acid is added to a lump of blue vitriol.
(b) Copper turnings are heated with concentrated nitric acid.
(c) Dil hydrochloric acid is added to silver nitrate solution.
(iv) Refer to the flow chart diagram below and give balanced equations with conditions if any for the following conversions A to D.

Answer:
(i) (a) Copper (II) oxide
(b) Nitrogen gas

(ii) (a) Vanadium pentoxide (V₂O₅)
(b) Ammonium chloride

(iii) (a) The blue coloured hydrated copper sulphate loses its water of crystallisation and white annhydrous copper (II) sulphate is formed.:

(b) The reddish brown nitrogen dioxide gas which has pungent smell is evolved along with the formation of (Cupric nitrate) and water.

(c) A thick curdy white precipitate of silver chloride is formed.
AgNO₃ + HCl → AgCl ↓ + HNO₃

Question 4.
(i) State the relevant reason for the following:
(a) Methane is called as marsh gas. Why?
(b) All glass apparatus are used in the laboratory preparation of HNO₃.
(ii) Name the ores of the given metals :
(a) Aluminium
(b) Zinc
(iii) Identify the terms for the following:
(a) Another name of nitric acid
(b) The catalyst used in the conversion of ethyne to ethane.
(c) A mixture of three parts of cone. HC1 and one part of cone. HNOj.
(iv) Copy and complete the following table : Column 3 has the names of gases to be prepared using the substance you enter in column 1 alongwith dilute or concentrated sulphuric acid as indicated by you in column 2.

Column 1 Substance reacted with acid	Column 2 Dilute or concentrated sulphuric acid (H2SO4)	Column 3 Gas
(a)		Hydrogen
(b)		Carbon dioxide
(c)		Only chlorine

Answer:
(i) (a) Methane is called as marsh gas because methane is formed by the decomposition of plant and animal matter lying under water in marshy areas.

(b) All glass apparatus are used in the laboratory preparation of HNO₃ because nitric acid being very corrosive and destroys the rubber or cork of the apparatus.

(ii) (a) Bauxite
(b) Calamine

(iii) (a) Aqua fortis
(b) Lindlar catalyst
(c) Aqua regia

(iv)

Column 1 Substance reacted with acid	Column 2 Dilute or concentrated sulphuric acid (H,S04)	Column 3 Gas
(a) Zinc	Dilute H2SO4	Hydrogen
(b) Copper carbonate	Dilute H2SO4	Carbon dioxide
(c) Sodium chloride + Manganese oxide	Concentrated H2SO4	Only chlorine

Question 5.
(i) (a) Write a balanced chemical equation for the laboratory preparation of nitric acid.
(b) Mention two precautions to be followed while carrying on the above experiment.
(ii) Select the correct answer from the brackets to complete the following statements:
(a) Haber’s process is used for industrial preparation of __________ (ammonium hydroxide/ammonium chloride/ammonia).
(b) Pure nitric acid is __________. (brown coloured/yellow coloured/colourless)
(iii) Give the IUPAC name of the following:

(iv) (a) Which of A and B is the cathode and which one is the anode?
(b) What is the electrolyte in the tank?

(c) What material is used for the cathode?
Answer:
(i) (a) KNO₃ + cone. H₂SO₄ → KHSO₄ + HNO₃ (below 200°C)
(b) 1. The reaction mixture should not be heated beyond 200°C because nitric acid decompose at highter temperatures.
2. The apparatus must be made of all glass as the vapours of nitric acid are corrosive therefore it damages the rubber and cork.

(ii) (a) Ammonia

(b) Colourless. (Pure nitric acid is colourless fuming liquid while commercial nitric acid is yellowish brown.)

(iii) (a) 2-Methyl butanoic acid
(b) 1,2-Dibromoethane
(c) Propan-2-ol

(iv) (a) A is cathode and B is anode.
(b) Molten fluorides of Al, Na and Ba.
(c) Graphite rods dipped in pure aluminium.

Question 6.
(i) Distinguish between the following:
(a) Alkane, alkene and alkyne [using potassium permanganate solution]
(b) Ethylene and Acetylene [ammonical solution of silver nitrate]
(ii) Give the formula of the next higher homologue of the following:
(a) Ethane.
(b) Ethene.
(iii)

(a) Name (i) the ammonium salt A (ii) alkaline gas C.
(b) How the conversion D is carried out ? State all the conditions like temperature, pressure and catalyst.
(c) (i) How is C converted to nitric oxide? Write the equation.
(ii) How is temperature maintained in above process?
(iii) Write the equation for conversion of F and G.
(iv) Draw the structural formula for each of the following:
(a) Isomer of n-butane.
(b) A three membered unsaturated hydrocarbon with a triple bond.
(c) The straight chain structure of 2-methyl butane.
(d) The mono-substituted product formed when ethane reacts with bromine gas.
Answer:
(i) (a)

Test	Alkanes	Alkenes	Alkynes
Alkaline Potassium Permanganate Test: Add a few drops of alkaline potassium permanganate sol. to the hydrocarbon.	No change takes place.	The purple colour of Potassium permanganate is decolourised.	The purple colour of potassium permanganate is decolorised.

(b) When acetylene is passed through an ammonical solution of silver nitrate, it gives a white precipitate of silver acetylide, while ethylene does not show any such reaction.

(ii) Propane – C₃H₈
(b) Propene – C₃H₆

(iii) (a) (i) Ammonium nitrate, NH₄NO₃
(ii) Ammonia

(b) D is mixed with hydrogen in the ratio of 1 : 3, compressd to a pressure of 200 to 500 atomosphere and passes over a catalyst (iron) heated to 450 to 500°C.

(c) (i) By passing the gas with excess of air over platinium gauze heated to 800°C.
4NH₃ + 5O₂ → 4NO + 6H₂

(ii) The oxidation of ammonia of nitric oxide is exothermic reaction and once the reaction is started it maintains the temperature of the platinium gauze.

(iii) 2N₂O + 2H₂O + O₂ → 4HNO₃
Ca(OH)₂ + 2HNO₃ → Ca(NO₃)₂ + 2H₂O

(iv) (a) Isomer of n-butane

(b) Propyne is the three membered unsaturated hydrocarbon with a triple bond.
H₃C – C ≡CH

(c) The compound n-pentane represents the straight chain structure of 2-methyl butane.

(d) The monosubstituted product formed when ethane reacts with bromine gas is bromoethane.

ICSE Class 10 Chemistry Question Papers with Answers