Students of ICSE Class 10 should refer to Study of Compounds Sulphuric Acid ICSE Class 10 Chemistry board year questions and solutions. below which have come in past board exams. You should always go through questions that have come in previous years. This will help you to understand the pattern of questions in ICSE Class 10 Chemistry and prepare accordingly. This will help you to get better marks in ICSE Class 10 Board Exams
ICSE Class 10 Chemistry Study of Compounds Sulphuric Acid Board Exam Questions
Students should learn the important questions and answers given below for Chapter Study of Compounds Sulphuric Acid in Chemistry for ICSE Class 10. These board questions are expected to come in the upcoming exams. Students of ICSE Class 10th should go through the below board exams questions and answers which will help them to get more marks in exams.
Board Exam Questions Study of Compounds Sulphuric Acid ICSE Class 10 Chemistry
(a) The conversion of sulphur dioxide into sulphur trioxide is an (1)………..therefore, (2)…… during the reaction. The reaction is (3)……… by (4)……….. . At low temperature, the reaction is (5)………. so an (6)………. of 500° C and a catalyst is needed, the reaction is accompanied by (7)……….. in volume and (8)……………… pressure (9)……………the yield of sulphur trioxide.
Answer
(1) exothermic reaction, (2) heat is evolved, (3) favoured, (4) low temperature, (5) slow, (6)
optimum temperature, (7) decrease, (8) high, (9) favours.
(b) Question. Sulphuric acid is a………acid.
Answer
non-volatile
Question. The physical property of concentrated sulphuric acid that makes it valuable in preparing other acids is its ………………….
Answer
high boiling point
Question. Sulphuric acid absorbs sulphur trioxide and forms……………
Answer
pyrosulphuric acid
Question. The acid anhydride of sulphuric acid is …………………………..
Answer
sulphur trioxide
Question. When hot concentrated sulphuric acid is added to sulphur, it gets oxidised to…………….
Answer
sulphur dioxide, SO2
Question. The reduced product obtained when hydrogen sulphide reacts with conc. sulphuric acid is…………
Answer
sulphur
Question. The salt which reacts with dil. sulphuric acid to form insoluble ppt is…………
Answer
Lead nitrate [Pb(NO3)2]
Question. The type of salt formed when excess of caustic soda reacts with sulphuric acid is…………
Answer
normal salt
Question. The gas produced by the action of concentrated sulphuric acid on sodium chloride is………….
Answer
HCl
Question. The dehydrated product obtained when sugar reacts with conc. sulphuric acid is………
Answer
carbon
Question. The chemical formula of oxalic acid is…………
Answer
C2H2O4
Question. The sulphur compound used for the identification of several cations is ………………. .
Answer
hydrogen sulphide
Question. An explosive prepared by using sulphuric acid is………
Answer
trinitrotoluene
Question. Sulphuric acid used for making fertilizers is made by the …………………………. process.
Answer
lead-chamber
Multiple Choice Questions
Question. Pyrosulphuric acid is the chemical name of :
(a) Green vitriol
(b) White vitriol
(c) Oleum
(d) Gypsum
Answer
C
Question. In the given equation identify the role played by concentrated sulphuric acid
S + 2H2SO4 ⎯→ 3SO2 + 2H2O :
(a) Non-volatile acid
(b) Oxidising agent
(c) Dehydrating agent
(d) None of the above
Answer
B
Question. When dilute sulphuric acid reacts with iron sulphide, the gas evolved is :
(a) Hydrogen sulphide
(b) Sulphur dioxide
(c) Sulphur trioxide
(d) Vapour of sulphuric acid
Answer
A
Question. 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
Question. When hot concentrated sulphuric acid is added to sulphur it gets oxidised to :
(a) H2S
(b) SO2
(c) O3
(d) HSO4
Answer
B
Question. When concentrated sulphuric acid reacts with NaOH, the product formed is :
(a) Sodium hydroxide
(b) Sodium sulphate
(c) Sodium carbonate
(d) Sodium hydrogen sulphate
Answer
B
Question. Dilute sulphuric acid will produce a white precipitate when added to a solution of :
(a) Copper nitrate
(b) Zinc nitrate
(c) Lead nitrate
(d) Sodium nitrate
Answer
C
Question Corrosive action of H2SO4 on skin is due to :
(a) Exothermic nature
(b) Volatile nature
(c) Dehydrating character
(d) Oxidising nature
Answer
C
Question. Nitroglycerine and nitrotoluene are :
(a) Fertilizers
(b) Explosives
(c) Fibres
(d) Detergents
Answer
B
Question. The molecular formula of epsom salt is :
(a) MgSO4 · 5H2O
(b) FeSO4 · 7H2O
(c) MgSO4 · 7H2O
(d) MgSO4 · 6H2O
Answer
A
Give One Word/Chemical Term
Question. Acid commonly known as oil of vitriol.
Answer
Sulphuric acid
Question. Calatyst used during contact process.
Answer
V2O5 or platinised asbestos
Question. Promoter used in contact process.
Answer
Potassium oxide
Question. Atomicity of sulphur.
Answer
Eight
Question. Basicity of sulphuric acid.
Answer
Dibasic
Question. Acid obtained by dissolving sulphur dioxide in water.
Answer
Sulphurous acid
Question. A black coloured substance formed when sugar is dehydrated.
Answer
Carbon or sugar charcoal
Question. Bleaching agent used to bleach delicate articles.
Answer
Moist sulphur dioxide
Question. Name the solution which turns colourless when sulphur dioxide gas is passed through it.
Answer
Potassium permanganate
Question. Name an acid that cannot be used to obtain sulphur dioxide, from sulphites.
Answer
Nitric acid
Question. Give the chemical name and common name of a reagent used in photographic work.
Answer
Sodium thiosulphate
Question. The process involved during the bleaching action of sulphur dioxide.
Answer
Reduction
Question. A neutral oxide of carbon formed when formic acid reacts with concentrated sulphuric acid.
Answer
Carbon monoxide
Question. Name the chemical used to test hydrogen sulphide.
Answer
Lead acetate
Question. Name an orange colour solution which turns in green colour when sulphur dioxide gas is passed through it.
Answer
Potassium dichromate
Question. An organic acid which on reaction with concentrated sulphuric acid, produces two oxides of carbon.
Answer
Oxalic acid
Question. The solution which turns black on coming in contact with hydrogen sulphide.
Answer
Lead acetate, lead nitrate solution
Question. Green coloured compound formed when SO2 is passed through acidified K2Cr2O7.
Answer
Chromium sulphate
Question. Process by which sulphur is boiled with rubber.
Answer
Vulcanization
Identification of Gases
Question. The gas which turns acidified potassium dichromate clear green.
Answer
Sulphur dioxide
Question. The gas produced on reaction of dilute sulphuric acid with a metallic sulphide.
Answer
Hydrogen sulphide
Question. The gas released when sodium carbonate is added to a solution of sulphur dioxide.
Answer
Carbon dioxide
Question. The gas produced by the action of concentrated sulphuric acid on sodium chloride.
Answer
Hydrogen chloride
Question. The gas evolved when dilute sulphuric acid is added to sodium sulphite.
Answer
Sulphur dioxide
State the Observation
Question. Concentrated sulphuric acid is added to a lump of blue vitriol.
Answer
1. When concentrated sulphuric acid is added to hydrated copper sulphate, it loses its water of crystallization and thus white annhydrous copper (II) sulphate is formed. In other words,
The blue coloured hydrated (II) sulphate turns white due to the loss of water of crystallization.
Question. Crystal of FeSO4.7H2O (Green) is placed in conc. sulphuric acid.
Answer
When the green coloured hydrated salt FeSO4.7H2O is placed in conc. H2SO4, it lose the water molecules and the solution becomes white. The colour and crystalline nature of hydrated salt is due to presence of water of crystallization in it.
Question. Lead nitrate is treated with dilute sulphuric acid.
Answer
Lead nitrate solution reacts with dilute sulphuric acid to form a white precipitate of lead sulphate, which is insoluble in all mineral acids.
Question. Dilute sulphuric acid is added to barium chloride.
Answer
Barium chloride solution when added to dilute sulphuric acid, a thick white precipitate of barium sulphate is obtained which is insoluble in all mineral acids. Hydrochloric acid is also formed.
BaCl2 + H2SO4 ⎯→ BaSO4↓ + 2HCl
Question. Sodium chloride is heated with conc. sulphuric acid.
Answer
Sodium chloride when heated with concentrated sulphuric acid, liberates pungent fumes of hydrogen chloride gas and sodium sulphate is formed.
Question. Dil. sulphuric acid is added to a solution of barium chloride and lead nitrate.
Answer
When dil. sulphuric acid is added to a solution of barium chloride and lead nitrate it forms a white precipitate of barium sulphate and lead sulphate respectively.
BaCl2 + H2SO4 ⎯→ 2HCl + BaSO4 ↓
Dil.
Pb (NO3)2 + H2SO4 ⎯→ PbSO4 + 2HNO3
Question. Dilute sulphuric acid is added to iron sulphide.
Answer
Iron sulphide reacts with dilute sulphuric acid to form iron (II) sulphate with the evolution of hydrogen sulphide gas, which has a rotten egg smell.
Question. Bleaching powder is heated with dil. sulphuric acid.
Answer
When bleaching powder is heated with dilute sulphuric acid, chlorine gas is liberated and calcium sulphate is formed along with water.
CaOCl2 + H2SO4 ⎯→ CaSO4 + H2O + Cl2↑
Chlorine
Question. Zinc metal is treated with dil sulphuric acid.
Answer
Zinc metal reacts with dilute sulphuric acid to liberate hydrogen gas and zinc sulphate is formed.
Zn + H2SO4 ⎯→ ZnSO4 ↓ + H2↑
White ppt. Hydrogen
Question. Carbon is heated with conc. sulphuric acid.
Answer
When carbon is heated with concentrated sulphuric acid, it is oxidised to carbon dioxide and the acid is reduced to sulphur dioxide.
C + 2H2SO4 ⎯→ CO2 + 2SO2 + 2H2O
Question. Sugar is heated with conc. sulphuric acid.
Balancing/Writing the Chemical Equations
(a) Write balanced chemical equation for the following :
1. Action of concentrated sulphuric acid on carbon.
Answer
2. Dilute sulphuric acid producing hydrogen.
Answer
3. Dilute sulphuric acid is poured over sodium sulphite.
Answer
4. Zinc reacts with conc. sulphuric acid.
Answer
5. Sodium bicarbonate and dilute sulphuric acid.
Answer
6. Sodium nitrate and conc. sulphuric acid.
Answer
7. Iron reacts with dil. sulphuric acid.
Answer
8. Sulphur is heated with concentrated sulphuric acid.
Answer
9. Concentrated sulphuric acid is poured over sugar.
Answer
10. Dilute sulphuric acid with copper carbonate.
Answer
11. Dilute sulphuric acid with lead nitrate solution.
Answer
12. Dilute sulphuric acid with zinc hydroxide.
Answer
13. Concentrated sulphuric acid with barium chloride.
Answer
14. Concentrated sulphuric acid with sulphur trioxide.
Answer
15. Sodium sulphite with dilute sulphuric acid.
Answer
16. Concentrated sulphuric acid with potassium chloride.
Answer
17. Concentrated sulphuric acid with zinc nitrate.
Answer
18. Concentrated sulphuric acid with potassium nitrate.
Answer
19. Potassium hydrogen carbonate and sulphuric acid.
Answer
20. Sodium nitrate and concentrated sulphuric acid.
Answer
Chemical Tests
1. Dilute sulphuric acid and dilute hydrochloric acid.
Answer
When barium chloride solution is added to the dilute sulphuric acid, thick white precipitate of barium sulphate is formed which is insoluble in any mineral acid such as nitric acid or hydrochloric acid.
BaCl2 + H2SO4 ⎯→ BaSO4 ↓ + 2HCl
(dil.)
With dilute hydrochloric acid, no effect is observe.
2. Chlorine gas and sulphur dioxide gas.
Answer
Chlorine gas turns starch iodide paper blue and sulphur dioxide gas turns moist acidified potassium dichromate paper green.
3. How will you distinguish between dilute hydrochloric acid and dilute sulphuric acid using lead nitrate solution ?
Answer
On adding lead nitrate to both acids, we will get a white precipitate. On heating the solution, the one whose precipitate will redissolve will be dil. HCl and the one with
insoluble precipitate will be dil. H2SO4. Actually on adding lead nitrate to HCl, PbCl2 precipitates out and on heating the solution it redissolves. But in case of H2SO4, PbSO4 is
formed which is insoluble even on heating it.
Pb(NO3)2 + 2HCl ⎯→ PbCl2 + 2HNO3
(dil.)
Pb(NO3)2 + H2SO4 ⎯→ PbSO4 + 2HNO3
(dil.)
Reasoning Based Questions
Q. 1. Why concentrated sulphuric acid is called the ‘oil of vitriol’ ?
Answer
Concentrated sulphuric acid is called ‘Oil of vitriol’ because of its oily appearance and the fact that it is present in vitrous or glassy substances like ferrous sulphate, alum, etc.
Q. 2. For the production of concentrated sulphuric acid, sulphur trioxide is not directly dissolved in water. Why ?
Answer
For the production of concentrated sulphuric acid, sulphur trioxide is not directly dissolved in water because with water, sulphur trioxide forms a mist of fine drops of sulphuric acid.
Q. 3. The impurity of arsenic oxide must be removed before passing the mixture of sulphur dioxide and air through the catalytic chamber in contact process. Why ?
Answer
This is because the impurity of arsenic oxide makes the catalyst poisonous.
Q. 4. Why concentrated sulphuric acid is kept in air tight bottles ?
Answer
Concentrated sulphuric acid readily absorbs moisture from atmosphere and gets diluted. Hence, it is kept in air tight bottles.
Q. 5. Why the level of concentrated sulphuric acid gets higher if it is left in an open vessel for a week ?
Answer
This is due to the hygroscopic nature of sulphuric acid. It absorbs water vapour from the atmosphere.
Q. 6. Why sulphuric acid behaves as an acid when diluted with water ?
Answer
When sulphuric acid is diluted with water, it ionizes almost completely into hydrogen ions (H+) and sulphate ions (SO42–)
H2SO4 ⇌ H+ + HSO4–
Hydrogen sulphate ion
HSO4 – H+ + SO42–
Sulphate ion
Since presence of H+ ions imparts acidic character, therefore, solution of sulphuric acid in water behaves as an acid.
Q. 7. Why the wooden shelves on which conc. sulphuric acid bottles are kept, stained black ?
Answer
Concentrated sulphuric acid is a very powerful dehydrating agent. It removes atoms of hydrogen and oxygen in the form of water from the cellulose [(C6H12O5)n], leaving behind carbon. It is black carbon which appears in the form of black stains.
Q. 8. A black spongy mass is formed, when concentrated sulphuric acid is added to sugar. Why ?
Answer
Sulphuric acid has great affinity for water, hence when concentrated sulphuric acid is added to sugar, it absorbs water from sugar by removing hydrogen and oxygen atoms in the ratio of 2 : 1 from sugar molecules. The sugar is charred producing black spongy mass of carbon, which is known as sugar charcoal.
C12H22O11 + H2SO4 ⎯→ 12C + [H2SO4 + 11H2O]
Sugar Sugar charcoal
Q. 9. When blue crystals of copper(II) sulphate are added to concentrated sulphuric acid crystals turn white. Why ?
Answer
Hydrated copper(II) sulphate, when added to concentrated sulphuric acid, loses water of crystallization and thus white anhydrous copper(II) sulphate is formed. The blue coloured hydrated copper(II) sulphate turns white due to the loss of water of crystallization.
CuSO4.5H2O + H2SO4 ⎯→ CuSO4 + [H2SO4.5H2O]
Hydrated copper Anhydrous copper
sulphate sulphate
(Blue crystals) (White crystals)
Q. 10. Why brisk effervescence is seen when H2SO4 is added to sodium carbonate ?
Answer
Brisk effervescence are seen due to the evolution of carbon dioxide gas.
Short Answer
Q. 1. Sulphuric acid is said to be dibasic acid. What is meant by the term ‘dibasic’ ?
Answer
Basicity of an acid is the number of H+ ions that one formula unit of an acid liberates, e.g.,
Monobasic = HCl, HNO3 etc.
Dibasic = H2SO4, H2SO3 etc.
Each acid can form as many kinds of salts, as it has hydrogen ions. Sulphuric acid can form two kinds of salts, i.e., SO42– and HSO4–. It ionizes in water to form two hydrogen ions. Hence, it is said to be dibasic.
H2SO4 ⇌ H+ + HSO4–
HSO4– ⇌ H+ + SO42–
These acids can yield two kinds of salts, i.e., the normal salt and the acid salt.
Q. 2. Some bacteria obtain their energy by oxidizing sulphur, producing sulphuric acid as a byproduct. In the laboratory, or industrially, the first step in the conversion of sulphur to sulphuric acid is to produce sulphur dioxide. Then sulphur dioxide is converted to sulphur trioxide which reacts with water, producing sulphuric acid.
(i) Name one catalyst used industrially which speeds up the conversion of sulphur dioxide to sulphur trioxide.
(ii) Write the equation for the conversion of sulphur dioxide to sulphur trioxide. Why does this reaction supply energy ?
(iii) What is the name of the compound formed between sulphur trioxide and sulphuric acid.
Answer
(i) Platinum and Vanadium pentaoxide.
(ii) When conversion of SO2 to SO3 takes place according to the following reaction.
SO2 + O2 ⎯→ 2SO3 + 45 k cal
The 45 k cal energy supplied by above reaction.
(iii) Oleum (H2S2O7).
Q. 3. (i) Write balanced equations for the three chemical reactions that take place during the conversion of sulphur dioxide to sulphuric acid in the contact process.
(ii) Name the catalyst used in the contact process.
(iii) Name another ore which on roasting gives sulphur dioxide.
Answer
(i) The chemical reactions are summarised as below :
S + O2 ⎯→ SO2
2SO2 + O2 ⎯→ 2SO3
SO3 + H2SO4 ⎯→ H2S2O7
(Oleum)
H2S2O7 + H2O ⎯→ 2H2SO4
(ii) Platinized asbestos or V2O5.
(iii) Zinc blende or ZnS :
2ZnS + 3O2 ⎯→ 2ZnO + 2SO2↑
Q. 4. (i) With the help of equations, give an outline for the manufacture of sulphuric acid by the contact process.
(ii) What property of sulphuric acid is shown by the reaction of concentrated sulphuric acid when heated with
(a) potassium nitrate (b) carbon ?
Answer
(i) Contact Tower :
(ii) (a) Non-volatile nature.
(b) Oxidising property.
Q. 5. (i) Which two gases are combined during contact process ?
(ii) Write the equation for the reaction between zinc and the final product of the contact process ?
(iii) What happens when sulphur trioxide gas is passed into concentrated sulphuric acid.
Answer
(i) SO2 and O2 (sulphur dioxide and oxygen)
(ii) Zn + 2H2SO4 ⎯→ ZnSO4 + 2H2O + SO2
(Conc.)
(iii) Sulphur trioxide gas dissolves in concentrated sulphuric acid to form fuming sulphuric acid, commonly known as oleum.
SO3 + H2SO4 ⎯→ H2S2O7
Oleum
Q. 6. While diluting concentrated sulphuric acid, the acid should be added to water and not water to the acid. Explain ?
Answer
When equal volumes of the acid and water are mixed at room temperature, the temperature may reach up to 120°C. Therefore, dilution of the acid should be done by adding small quantity of acid into water.
If water is added to concentrated sulphuric acid, the molecules of the acid try to grasp the molecules of water resulting in molecular tension, liberating heat and due to sudden rise in temperature, the acid starts splashing.
If a drop of concentrated acid is added to water, the molecules of acid go in different directions to pick up water which is available in plenty. Although the same amount of heat is formed but since the molecules are spread out, no splashing occurs.
Q. 7. (i) Which property of sulphuric acid is used to prepare the hydrochloric and nitric acid respectively.
(ii) What is the catalyst used in catalytic chamber and what is the temperature used ?
Answer
(i) Non-volatile nature of sulphuric acid is responsible to prepare HCl and HNO3 by using H2SO4.
(ii) The catalyst used is platinized asbestos or vanadium pentaoxide and the temperature used is about 450°C.
Q. 8. (i) (a) Name the acid formed when sulphur dioxide dissolves in water.
(b) What are the two necessary conditions for the direct combination of sulphur dioxide and chlorine forming sulphuryl chloride ?
(c) State the property of sulphur dioxide which causes potassium permanganate to change its colour from purple to colourless.
(ii) Answer the following questions related to dilute and concentrated sulphuric acid.
(a) Which acid does not react with metals that are placed below hydrogen in activity series ?
(b) Which acid will give white precipitates with barium sulphate.
Answer
(i) (a) Sulphurous acid.
(b) Sunlight and absence of moisture.
(c) Reducing.
