Acid, Bases and Salts

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Class 10 Science Chapter 2
Acid, Bases and Salts
Important Questions

Here are some critical Chapter 2 Acid, Bases and Salts problems for Class 10 Science. These inquiries are intended to aid students in studying for and performing well on the CBSE Class 10 Science Examination 2024–25. Students can clear up their concerns and be ready for the exams by practising different types of questions. By answering these questions, you’ll increase your confidence while also sharpening your problem-solving abilities.

Table of Contents

Introduction

In Chapter 2 of Acid, Bases and Salts you will learn about The Chemical Properties of Acids and Bases, Common Characteristics of Acids and Bases, Strong Acid and Base Solution and Characteristics of Salts.

Class 10 Acid Bases and Salts Important Questions and Answers

Q 1. During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to:

Options

(a) Absorb the evolved gas
(b) Moisten the gas
(c) Absorb moisture from the gas
(d) Absorb Cl– ions from the evolved gas

Ans. (c)

Explanation:
During the preparation of hydrogen chloride gas, especially on a humid day, the gas may carry moisture due to the presence of water vapour in the air. Calcium chloride (CaCl₂) is a drying agent, and its role in the guard tube is to absorb any moisture from the hydrogen chloride gas, ensuring that the gas remains dry.

Q 2. In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus was set up. Which among the following statement(s) is(are) correct?

(i) Bulbs will not glow because electrolyte is not acidic.
(ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
(iii) Bulb will not glow because the circuit is incomplete.
(iv) Bulb will not glow because it depends upon the type of electrolytic solution.

Options

(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) only
(d) (iv) only

Ans. (c)

Explanation:
Statement (ii) is correct because NaOH is a strong base that dissociates completely in water to furnish ions (Na⁺ and OH⁻), which can conduct electricity, causing the bulb to glow.

Q 3. Give balanced chemical equation for reaction of acids with metal carbonate.

Explanation:
The general reaction of an acid with a metal carbonate produces salt, carbon dioxide (CO₂), and water (H₂O). The balanced chemical equation for this reaction is:

Acid + Metal carbonate → Salt $+ CO_2 + H_2O \\[5 bp]$

For example, when hydrochloric acid (HCl) reacts with calcium carbonate (CaCO₃), the balanced chemical equation is:

$2HCl(aq) + CaCO_3(s) \to CaCl_2(aq) +CO_2(g) + H_2O(l)$

Q 4. Write an equation for the reaction of iron with steam. Name the compound of iron obtained.

Explanation:
When iron reacts with steam, it forms iron(III) oxide (Fe₃O₄) and hydrogen gas (H₂). The reaction takes place at high temperatures. The balanced chemical equation is:

3Fe(s) + 4H_2O(g) → Fe_3O_4(s) + 4H_2(g) \\ [5 bp]

The compound of iron obtained is iron(III) oxide (Fe₃O₄).

Q 5. Crystals of a substance changed their colour on heating in a closed test tube but regained it after sometime when they were allowed to cool down. Name the substance and write its formula and explain the phenomenon involved.

Explanation:
The substance is likely copper(II) sulphate pentahydrate (CuSO₄·5H₂O).

Explanation of the Phenomenon:

On heating, copper(II) sulphate pentahydrate (CuSO₄·5H₂O) loses its water of crystallisation, turning from blue to white because the anhydrous form of copper sulphate (CuSO₄) is white.

$CuSO_4⋅5H_2O(s)\underrightarrow{\space \space \text{HEAT}\space \space } CuSO_4(s) + 5H_2O(g) \\[5 bp]$

On cooling, when the substance is exposed to moisture in the air, it absorbs water and regains its blue colour, returning to its hydrated form.

$CuSO_4(s) + 5H_2O(l) \to CuSO_4\cdot5H_2O(s)$

CBSE Class 10 Science Chapter wise Important Questions

Chapter No.	Chapter Name
Chapter 1	Chemical Reactions and Equations
Chapter 2	Acid, Bases and Salts
Chapter 3	Metals and Non-Metals
Chapter 4	Carbon and its Compounds
Chapter 5	Life Processes
Chapter 6	Control and Coordination
Chapter 7	How do Organisms Reproduce
Chapter 8	Heredity
Chapter 9	Light : Reflection and Refraction
Chapter 10	The Human Eye and the Colourful world
Chapter 11	Electricity
Chapter 12	Magnetic Effects of Electric Current
Chapter 13	Our Environment

Conclusion

oswal.io offers a thorough set of questions for learning the topic in a better way if you’re looking to further practise and improve your grasp of the concepts covered in the chapter.

Frequently Asked Questions

Q1. What is salt in acids, bases and salts?

Ans: In chemistry, a salt is a substance obtained by the reaction of an acid and a base.Salts are composed of positive ions (cations) of bases and negative ions (anions) of acids. The reaction of acid and base is called the neutralisation reaction.

Q2. Is $NH_4Cl$ a basic salt?

Ans: Ammonium chloride (chemical formula

NH_4Cl

is an acid salt because it is a salt of a strong acid (i.e. hydrochloric acid) and a weak base (i.e. ammonium hydroxide).

Q3. What are the 2 types of acids?

Ans:There are two basic types of acids: organic and inorganic acids. Inorganic acids are sometimes referred to as mineral acids. As a group, organic acids are generally not as strong as inorganic acids. The main difference between the two is the presence of carbon in the compound; inorganic acids do not contain carbon. Inorganic acids – Inorganic acids are often termed mineral acids. The anhydrous form may be gaseous or solid. An inorganic anhydride is an oxide of metalloid which can combine with water to form an inorganic acid. Example:Sulphuric acid

(H_2SO_4)

,Phosphoric acid

(H_3PO_4)

,Nitric acid

(HNO_3)

‍Organic acids – Organic acids are corrosive and toxic. Corrosivity is a form of toxicity to the tissues that the acid contacts. Organic acids and their derivatives cover a wide range of substances. They are used in nearly every type of chemical manufacture. Because of the variety in the chemical structure of the members of the organic acid group. Example:Acetic acid ,Citric acid ,Formic acid.

Q4. Is salt basic or acidic?

Ans: The salt is basic only when it contains a weak acid conjugate base. For example, sodium chloride contains chloride

(Cl^-)

, the conjugate base of HCl.

Q5. What happens when salt reacts with HCl?

Ans: When an acid reacts with metal, a salt and hydrogen are produced: acid + metal → salt + hydrogen The salt that is produced depends upon which acid and which metal reacts.Sodium metal reacts with hydrochloric acid which produces hydrogen gas and sodium chloride.

2Na(s)+2HCl(aq)\to2NaCl(aq)+H_2(g)

Chapter Wise Important Questions for CBSE Board Class 10 Science
Chemical Reactions and Equations
Acid, Bases and Salts
Metals and Non-Metals
Carbon and its Compounds
Life Processes
Control and Coordination
How do Organisms Reproduce
Heredity
Light : Reflection and Refraction
The Human Eye and the Colourful world
Electricity
Magnetic Effects of Electric Current
Our Environment

Class 10 Science Chapter 2 Acid, Bases and Salts Important Questions

Introduction

Class 10 Acid Bases and Salts Important Questions and Answers

Q 1. During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to:

Options

(a) Absorb the evolved gas (b) Moisten the gas (c) Absorb moisture from the gas (d) Absorb Cl– ions from the evolved gas

Q 2. In an attempt to demonstrate electrical conductivity through an electrolyte, the following apparatus was set up. Which among the following statement(s) is(are) correct?

(i) Bulbs will not glow because electrolyte is not acidic. (ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction. (iii) Bulb will not glow because the circuit is incomplete. (iv) Bulb will not glow because it depends upon the type of electrolytic solution.

Options

(a) (i) and (iii) (b) (ii) and (iv) (c) (ii) only (d) (iv) only

Q 3. Give balanced chemical equation for reaction of acids with metal carbonate.

Q 4. Write an equation for the reaction of iron with steam. Name the compound of iron obtained.

Q 5. Crystals of a substance changed their colour on heating in a closed test tube but regained it after sometime when they were allowed to cool down. Name the substance and write its formula and explain the phenomenon involved.

CBSE Class 10 Science Chapter wise Important Questions

Conclusion

Frequently Asked Questions

Q1. What is salt in acids, bases and salts?

Q2. Is NH_4Cl a basic salt?

Q3. What are the 2 types of acids?

Q4. Is salt basic or acidic?

Q5. What happens when salt reacts with HCl?

Class 10 Science Chapter 2
Acid, Bases and Salts
Important Questions

(a) Absorb the evolved gas
(b) Moisten the gas
(c) Absorb moisture from the gas
(d) Absorb Cl– ions from the evolved gas

(i) Bulbs will not glow because electrolyte is not acidic.
(ii) Bulb will glow because NaOH is a strong base and furnishes ions for conduction.
(iii) Bulb will not glow because the circuit is incomplete.
(iv) Bulb will not glow because it depends upon the type of electrolytic solution.

(a) (i) and (iii)
(b) (ii) and (iv)
(c) (ii) only
(d) (iv) only

Q2. Is $NH_4Cl$ a basic salt?