Selina Concise Chemistry Solution for ICSE Class 10 Chapter 11 Sulphuric Acid

In chemistry, sulphuric acid is one of the most common acids that students come across while conducting experiments. Thus, in chapter 11 of Selina chemistry textbook students will read all about sulphuric acid – its properties, manufacturing process as well as its behaviour as an acid when diluted or concentrated. Keeping this objective in mind, we are offering free concise chemistry class 10 ICSE Solutions for chapter 11 – sulphuric acid here to further make studying much easier.

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1. Why is water not added to concentrated H₂SO₄ in order to dilute it?

Solution:

The reaction between water and concentrated H₂SO₄ is an exothermic reaction. If water is added to the concentrated acid, the temperature increases suddenly. As the acid is in larger quantity, it gushes out enormously with severe repercussions.

2. What is the name given to the salts of:

(a) Sulphorous acid (b) Sulphuric acid

Solution:

The name given to salts are:

(a) Sulphorous acid – Its salt is known as Sulphite salt. Example – Na₂SO₃: Sodium Sulphite

(b) Sulphuric acid – Its salt is known as sulphate. Example – CuSO₄: Copper sulphate

3. Give the odour of gas evolved and name the gas produced when sodium sulphide is added to a solution of HCl in the water?

Solution:

The gas that is evolved when sodium sulphide is added to a solution of HCl is Hydrogen sulphide. The odour of Hydrogen sulphide is that if rotten eggs.

4. Which property of sulphuric acid accounts for its use as a dehydrating agent?

Solution:

The property of sulphuric acid accounting for its property of a dehydrating agent is its strong affinity towards water.

5. (a) Name the acid formed when sulphur dioxide dissolves in water

(b) Name the has released when sodium carbonate is added to a solution of sulphur dioxide.

Solution:

1. When sulphur dioxide is dissolved in water, sulphourous acid is formed
2. When sodium carbonate is added to a solution of sulphur dioxide, carbon dioxide is released.

6. Comment, sulphuric acid is referred to as

(a) King of chemicals

(b) Oil of vitriol

Solution:

1. King of chemicals – Sulphuric acid is often referred to as the king of chemicals. It is a highly corrosive, strong acid and has a myriad of applications. It is involved in some or the other way to manufacture everything practically. As no other synthetic compound is used by so many industries on this big a scale, it is referred to as the king of chemicals.
2. Sulphuric acid is referred to as oil of vitriol as the process of its attainment was as an oily viscous liquid when crystals of green vitriol were heated.

7. Why the impurity of arsenic oxide must be removed before passing the mixture of SO₂ and air through the catalytic chamber?

Solution:

Impurities of arsenic oxides must be removed before it is passed through the mixture of SO₂ and air through the catalytic chamber as these impurities are toxic to the catalyst. It poisons thereby deactivating the catalyst.

8. Give a chemical test to distinguish between:

(a) dilute sulphuric acid and dilute hydrochloric acid,

(b) dilute sulphuric acid and conc. Sulphuric acid

Solution:

(a)The test that can be used to distinguish dilute sulphuric acid and dilute hydrochloric acid is BaCl₂ test – Barium chloride test.

When a solution of BaCl₂ is added to dilute sulphuric acid and dilute hydrochloric acid, it forms a white precipitate with H₂SO₄ to produce BaSO₄. On the other hand, dilute HCl does not react at all.

(b) When zinc is treated with dilute sulphuric acid, it releases hydrogen gas that bums out with a sound and when zinc reacts with concentrated sulphuric acid, it releases SO₂ gas which in turn turns the acidified potassium dichromate paper into green colour.

9. Copy and complete the following table:

Solution:

The completed table is as follows:

10. Concentrated sulphuric acid is both an oxidizing agent and a non-volatile acid. Write one equation. Each to illustrate the above-mentioned properties of sulphuric acid.

Solution:

Concentrated sulphuric acid – an oxidizing agent:

This is because concentrated sulphuric acid upon thermal decomposition produces nascent oxygen [O]. The equation illustrating the same is as follows:

Concentrated sulphuric acid – a non-volatile acid:

It is referred to as a non-volatile compound as it has a high boiling point, approximately 338˚C. This property of concentrated sulphuric acid is made use to prepare volatile acids such as nitric acids, hydrochloric acids from their salts through double decomposition.

The equation illustrating the same is as follows:

11. Sulphuric acid is manufactured by the contact process

(a) Give two balanced equations to obtain SO₂ in this process

(b) Give the conditions for the oxidation of SO₂

(c) Name the catalyst used

(d) Why H₂SO₄ is not obtained by directly reacting SO₃ with water

(e) Name the chemical used to dissolve SO₃ and also name the product formed

(f) Name a gas that can be oxidized to sulphur

Solution:

1. Following are two reactions to obtain SO₂ from the contact process:

1. Oxidation of SO₂ requires the following conditions:

• The catalyst to be used – platinized asbestos or vanadium pentoxide(V₂O₅)
• Production of sulphur trioxide increases as a result of excess oxygen
• As the formed product has a lesser volume than the reactant, high pressure of 2 atm is required
• A low temperature should be maintained. The temperature range of 410˚C – 450 ˚C is known to produce maximum yield

1. The catalyst that is used in the contact process is vanadium pentoxide(V₂O₅)
2. This is because it is an exothermic reaction. This produces small misty droplets of sulphuric acid which is not absorbed directly by water
3. Concentrated sulphuric acid is the chemical used to dissolve SO₃. The resultant is the oleum.
4. A gas that can be used to oxidize sulphur is hydrogen sulphide

12. Some properties of sulphuric acid are listed below. Choose the property A, B, C or D which is responsible for the reactions (i) to (v). Some properties may be repeated:

A. Acid

B. Dehydrating agent

C. Non-volatile acid

D. Oxidizing agent

Solution:

1. B
2. D
3. C
4. A
5. A

13. Why is:

(a) Concentrated sulphuric acid kept in airtight bottles?

(b) H₂SO₄ is not a drying agent for H₂S?

(c) Sulphuric acid is used in the preparation of HCl and HNO₃? Give the equation in both cases.

Solution:

1. Concentrated sulphuric acid is stored in airtight bottles as it is a hygroscopic substance absorbing moisture on being exposed to air.
2. H₂SO₄ forms sulphur upon reacting with H₂S hence is not used as a drying agent.

1. Concentrated sulphuric acid is considered as non-volatile as it has a high boiling point. This is the reason why it is used to prepare volatile acids such as Hydrochloric acid and nitric acids from their salts through the process of double decomposition.

14. What property of conc. H₂SO₄ is made use of in each of the following cases? Give an equation for the reaction on each case

(a) In the production of HCl gas when it reacts with a chlorine

(b) In the preparation of CO from HCOOH

(c) As a source of hydrogen by diluting it and adding a strip of magnesium

(d) In the preparation of sulphur dioxide by warming a mixture of conc. Sulphuric acid and copper-turnings

(e) Hydrogen sulphides gas is passed through concentrated sulphuric acid

(f) Its reaction with (i) ethanol (ii) carbon

Solution:

1. On heating with NaCl, concentrated sulphuric acid evolves pungent fumes of HCl gas.

Property: It’s reducing property.

1. Preparation of CO from HCOOH: Property – as a dehydrating agent.

1. Acidic property: As per the reactivity series, magnesium is present above hydrogen hence sulphuric acid is able to release hydrogen gas upon reacting with magnesium strips

1. Oxidizing property – this property of concentrated sulphuric acid is due to thermal decomposition.

1. When hydrogen sulphide is passed through concentrated sulphuric acid, it releases sulphur dioxide to form sulphur.

1. Conc. H₂SO₄ when reacts with ethanol and carbon produces the following:
2. Reaction with Ethanol

1. Reaction with carbon

15. (a) Give the equation for:

(i) Heat on sulphur with conc.sulphuric acid

(ii) Reaction of – sugar with conc.sulphuric acid

1. Give a balanced equation for the conversion of zinc oxide to zinc sulphate
2. Select the correct answer from A,B, C
3. Sodium hydroxide solution
4. A weak acid
5. Dilute sulphuric acid

The solution which liberates sulphur dioxide gas, from sodium sulphite

Solution:

16. (a)In the manufacture of sulphuric acid by contact process, give the equation for the conversion of sulphur trioxide to sulphuric acid

(b) Give equations for the action of sulphuric acid on

(i) Potassium hydrogen carbonate

(ii) Sulphur

1. Identify the acid in each case
2. The acid which produces sugar charcoal from sugar
3. Acid on mixing with lead nitrate solution produces white ppt. which is insoluble even on heating

Solution:

17. Give reasons for the following.

(a) Sulphuric acid forms two types of salts with NaOH

(b) Red brown vapours are produced when concentrated sulphuric acid is added to hydrogen bromide

(c) A piece of wood becomes black when concentrated sulphuric acid is poured on it

(d) Brisk effervescence is seen when oil of vitriol is added to sodium carbonate

Solution:

18. Name the products formed when hot and concentrated sulphuric acid reacts with the following:

(a) Sulphur

(b) NaOH

(c) Sugar

(d) Carbon

(e) Copper

Solution:

Name of the product	Reaction with hot and concentrated sulphuric acid	Produces	Reaction
Sulphur		Sulphur dioxide
NaOH		Sodium sulphate
Sugar		Carbon
Carbon		Carbon dioxide and sulphur dioxide gas
Copper		Copper sulphate and sulphur dioxide

19. (a) Name the gas produced on the reaction of dilute sulphuric acid with a metallic sulphide

(b) Some properties of sulphuric acid are listed below. Choose the role played by sulphuric acid as A, B, C or D which is responsible for the reactions (i) to (v). Some role/s may be repeated

1. Dilute acid

2. Dehydrating agent

3. Non-volatile acid

4. Oxidizing agent

1. Give a balanced equation for the reaction: Zinc sulphide and dilute sulphuric acid

Solution:

1. The gas produced on the reaction of dilute sulphuric acid with a metallic sulphide is Hydrogen sulphide (H₂S)
2. (i) Dehydrating agent

(ii) Oxidizing agent

(iii) Non-volatile acid

(iv) Dilute acid

(v) Oxidizing agent

(c) The balanced equation for the reaction: Zinc sulphide and dilute sulphuric acid is as follows:

20. (a) State one appropriate observation for Conc.H₂SO₄ is added to a crystal of hydrated copper sulphate

(b) In the given equation –

Identify the role played by conc.H₂SO₄

1. Non-volatile acid
2. Oxidising agent
3. Dehydrating agent
4. None of the above
5. Give a balanced equation for Dehydration of concentrated sulphuric acid with sugar crystals
6. Identify the substance underlined: A dilute mineral acid which forms a white precipitate when treated with a barium chloride solution

Solution:

1. The water of crystallization is eliminated from salt when concentrated H₂SO₄ is added to a crystal of hydrated copper sulphate
2. Conc. H₂SO₄ acts as an oxidizing agent
3. 
4. The underline substance is sulphuric acid H₂SO₄. When it is treated with barium chloride, it forms a white precipitate.

These solutions contain detailed information and answers prepared by experts that will help students understand each topic clearly and tackle all the important questions given in the chapter. Moreover, students can easily download the solutions in the form of a PDF and use them to study effectively, have a quick glance of the entire chapter and ultimately score higher marks in the examinations.

The given solutions are as per the 2019-20 Concise Selina textbook. The Selina Solutions for the academic year 2020-21 will be updated soon.