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NCERT Solutions for Class 10 Chemistry Chapter 2 : Acids, Bases and Salts

NCERT Solutions for Class 10 Science Chapter 2 Acids, Bases, and Salts deals with the in-depth understanding of why substances have different tastes and properties. Students preparing for acid base and salts class 10 will get to learn about the nature and behaviour of acids, bases, and salts in this chapter. This chapter primarily explains the chemical properties of acids, bases, and salts, as well as their interactions with metals, nonmetals, and one another. It covers all major concepts in detail, allowing students to understand the ideas better. NCERT Solutions acids bases and salts class 10 the second chapter of the section, concentrates on the various concepts of acids, bases and salts. Students will study the definitions of Acids and Bases in terms of supplying of H+ and OH- ions, their properties, examples and uses, pH scale concept; manufacture and uses of Sodium Hydroxide, Bleaching powder, Baking soda, Washing soda, etc., which is useful in last-minute subject preparation. This chapter will also teach students about salts, their properties, pH, the compounds derived from salt, and the nature and properties of salt crystals. Acids Bases and Salts Class 10 solutions are extremely beneficial for achieving high exam scores and thoroughly prepare you for all of the major subjects. Our experts' NCERT Solutions attempt to provide all-around clarity of questions.

Table of Content

Introduction

Access NCERT Solutions for Class 10 Chemistry Chapter 2 : Acids, Bases and Salts

In Text Page 18

Question 1

You have been provided with three test tubes, one of them contains distilled water and the other two contain an acidic solution and a basic solution respectively. If you are given only red litmus paper; how will you identify the contents of each test tube?

Easy

Solution

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Add few drops of solution from all three test tubes on the red litmus paper separately. The solution which turns red litmus to blue contains basic solution. Use this blue litmus paper to test the solutions in other two test tubes. The solution from the test tube which turns blue litmus paper to red will be the acidic solution and solution of the test tube which do not change either red or blue litmus paper contain water.

Question 2

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:

N a C l

H C l

L i C l

K C l

Medium

Solution

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Crushed egg shell has composition

C a C O_{3}

reacts with acid and gives gas

C O_{2}

which turns lime water

(C a (O H)_{2})

milky by producing

C a C O_{3}

again. The acid in given options is

H C l

C a C O_{3} + 2 H C l \to C a C l_{2} + C O_{2} + H_{2} O

C a (O H)_{2} + C O_{2} \to C a C O_{3} + H_{2} O

Question 3

10 m L

of a solution of

N a O H

is found to be completely neutralised by

8 m L

of a given solution of

H C l

. If we take

20 m L

of the same solution of

N a O H

, the amount

H C l

solution (the same solution as before) required to neutralise it will be:

4 m L

8 m L

12 m L

16 m L

Hard

Solution

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Reaction of

H C l

and

N a O H

is:

N a O H + H C l \to N a C l + H_{2} O

1 m o l

N a O H

is neutralized by

1 m o l

H C l

. If

10 m l

N a O H

is neutralize by

H C l = 8 m l

1 m l

N a O H

will neutralize by

H C l = \frac{8}{1 0} m l

20 m l

N a O H

for neutralization will require

H C l = 0.8 \times 20 m l = 16 m l

So, the correct option is

D

Question 4

Which one of the following types of medicines is used for treating indigestion?

Antibiotic

Analgesic

Antacid

Antiseptic

Medium

Solution

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C o r r e c t O p t i o n

C

E x p l a n a t i o n f o r c o r r e c t a n s w e r :

A n t a c i d

:
The antacid is a class of drug which neutralises the excessive acid produced in the stomach. This drug is used to treat acidity. For example: milk of magnesia.

E x p l a n a t i o n f o r i n c o r r e c t a n s w e r :

The pain-relieving drugs are called analgesics. For example: Aspirin

Antiseptics are antimicrobial drugs that are applied to living tissue/skin to reduce the possibility of infection. For example: Iodine tincture.

Antibiotics are a group of medicines that are used to treat infections caused by microorganisms and parasites. For example: Penicillin.

F i n a l A n s w e r :

Option

C

Question 5

Write word equations and then balanced equations for the reaction taking place when:
(a) Dilute sulphuric acid reacts with zinc granules.
(b) Dilute hydrochloric acid reacts with magnesium ribbon.
(c) Dilute sulphuric acid reacts with aluminium powder.
(d) Dilute hydrochloric acid reacts with iron filings.

Medium

Solution

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a) Dilute sulphuric acid reacts with zinc granules to produce zinc sulphate and hydrogen gas

H_{2} S O_{4} (a q) + Z n (s) \to Z n S O_{4} (a q) + H_{2} (g)

(b) Dilute hydrochloric acid reacts with magnesium ribbon to produce magnesium chloride and hydrogen gas.

2 H C l (a q) + M g (s) \to M g C l_{2} (a q) + H_{2} (g)

3 H_{2} S O_{4} (a q) + 2 A l (s) \to A l_{2} (S O_{4})_{3} (a q) + 3 H_{2} (g)

(d) Dilute hydrochloric acid reacts with iron filings to produce ferric chloride and hydrogen gas.

6 H C l (a q) + F e (s) \to 2 F e C l_{3} (a q) + 3 H_{2} (g)

Question 6

Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an activity to prove it.

Hard

Solution

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Activity:

Nails are fitted in a cork and are kept in a 100 ml beaker. Then these are connected to the two terminals of a 6 volt battery along with a bulb and a switch. Now some dilute

H C l

is poured in the beaker and current is allowed to pass through the circuit. The same experiment is carried out using glucose and alcohol solutions separately in place of

H C l

Observations:

The bulb glows in

H C l

solution only. The reason is that

H C l

solution dissociates into

H^{+}

and

C l^{-}

ions which help to conduct electricity while glucose and alcohol solutions do not dissociate into ions and so, do not conduct electricity. That is why we find the bulb glowing in

H C l

solution only.

Conclusions:

The above activity proves that acids contain hydrogen but not all compounds containing hydrogen are acids. Due to this reason, compounds such as alcohols and glucose despite containing hydrogen, are not categorized as acids.

Question 7

Why does distilled water not conduct electricity, whereas rain water does?

Medium

Solution

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Distilled water is pure form of water which do not contain any solute in it. Therefore it cannot conduct electricity because it does not contain ions while rain water contains dissolved salts and acids which dissociates in ions and conducts electricity.

Question 8

Why do acids not show acidic behaviour in the absence of water?

Medium

Solution

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Hint: Acids are compounds that release $H^{+}$ ions easily.

Explanation of answer:

Water is known as a universal solvent as maximum compounds are easily soluble in it.
In water majority of compounds dissociate into their constituent ions.
The acidic behavior of acid is due to the presence of hydrogen ions $H^{+}$ as $p H$ is directly proportional to $H^{+}$ concentration.
In the absence of water, an acid will not show its acidic behavior because acids do not dissociate to produce $H^{+} (a q)$ ions.
For example, hydrochloric acid can easily release its $H^{+}$ ion in water to form hydronium ion $H_{3} O^{+}$ and $C l^{-}$ ion.

Question 9

Five solutions

A, B, C, D

and

E

when tested with universal indicator showed pH as

4, 1, 11, 7

and

9

, respectively. Which solution is:

(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

Medium

Solution

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D

is neutral, as its

p H

value is equal to 7

C

is strongly alkaline, as its

p H

value is 11.

B

is strongly acidic, as its

p H

value is equal to 1

A

is weakly acidic, as its

p H

value is equal to 4 and more than solution

B

E

is weakly alkaline, as its

p H

value is equal to 9 and less than

C

p H

value of the given solution in increasing order of hydrogen-ion concentration:

11 < 9 < 7 < 4 < 1

Question 10

Equal lengths of magnesium ribbons are taken in test tubes

A

and

B

. Hydrochloric acid

(H C l)

is added to test tube

A

, while acetic acid

(C H_{3} C O O H)

is added to test tube

B

. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why?

Medium

Solution

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Magnesium metal when reacts with an acid gives off hydrogen gas in the reaction. In test tube

A

fizzing occurs more vigorously because

H C l

is stronger acid than acetic acid. Hence,

H C l

liberates hydrogen gas more vigorously, which causes fizzing more vigorously.

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NCERT Solutions for Class 10 Chemistry Chapter 2 : Acids, Bases and Salts

NCERT Solutions for Class 10 Science Chapter 2 Acids, Bases and Salts – Brief Overview

Every chemical substance we encounter contains some form of nature. In terms of chemicals, however, we associate nature with either acidic, basic, or neutral nature. Indicators are chemicals whose solutions change colour when the pH changes. They denote whether the solution is acidic or basic.

Acids

According to the Arrhenius theory, Acid is any chemical, when dissolved in water, can donate a hydrogen ion (H+) to another molecule or compound. Acids are hydrogen-containing chemicals that dissociate in water to produce H+ ions or protons. Acids are also sour in taste. A few examples of acids are: Hydrochloric acid (HCl), Sulphuric acid (H₂SO₄), Nitric acid (HNO₃), Phosphoric acid (H₃PO₄)

Classification of Acids depending upon their source

Natural/Organic Acids – Natural Acids or Organic Acids are acids derived from natural sources. Example: Oxalic acid, Acetic acid, Citric acid, etc.
Mineral/Inorganic Acids – Mineral acids are acids that are generated from minerals. Inorganic acids, man-made acids, or synthetic acids are also mineral acids. Example: Sulphuric acid, Nitric acid, Carbonic acid, etc.

Classification of Acids depending upon their strength

Strong Acids – The acid that entirely dissociates into hydrogen ions is known as a strong acid. Example: Hydrochloric acid, Nitric acid, etc.
Weak Acids – Weak acid is an acid that is slightly ionized in water and hence creates a tiny number of hydrogen ions (H+). Example: Acetic acid, Carbonic acid, etc.

Bases

According to the Arrhenius theory, Bases are hydroxide compounds that dissociate in water to form hydroxide ions (OH-). In water, bases ionize to form hydroxide ions (OH-). Bases are also bitter in taste. A few examples of bases are: Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)₂), Potassium hydroxide (KOH)

Classification of Bases on the basis of their solubility

Soluble – Bases soluble in water are called alkalis. Alkali is considered a strong base

Classification of Bases on their strength

Strong Bases – They completely dissociate in water to give hydroxide ions.
Weak Bases – They partially dissociate in water to give hydroxide ions.

How do acids and bases react with each other?

When acids and bases react with each other, they produce salt and water. This is known as a neutralization reaction.

Acid + Base → Salt + Water

For example,

HCl (Acid) + NaOH (Base) → NaCl (Salt) + H₂O (Water)

H₂SO₄ + Ca(OH)₂ → CaSO₄ + 2H₂O

pH Value

A pH scale is used to determine the acidity or basicity of an aqueous solution. The pH of acidic solutions is lower than that of basic or alkaline solutions. The pH scale consists of scales ranging from 0 to 14.

For acidic solutions : pH < 7

For water or neutral solutions : pH = 7

For basic solution : pH > 7

Salts

Salts are ionic substances formed as a result of the neutralization process between acid and base. Salts have no electrical charge. The majority of the salts have crystalline soils. Salts can be either transparent or opaque. The majority of the salts are water-soluble. They are classed as follows:

Acidic Salts – Salts formed due to a reaction between a strong acid and a weak base.
Neutral Salts – Formed when equally strong or weak acids and bases react with each other
Basic Salts – Salts formed due to a reaction between a strong base and weak acid

Related Chapters

Chapter 1 : Chemical reactions

Chapter 3 : Metals and Non metals

Chapter 4 : Carbon and its compounds

Chapter 5 : Periodic Classification of Elements

Chapter 6 : Life Processes

Chapter 7 : Control and Co-ordination in Plants and Animals

Chapter 8 : Reproduction

Chapter 9 : Heredity and Evolution

Chapter 10 : Light- Reflection and Refaction

Chapter 11 : The Human Eye and colourful World

Chapter 12 : Electricity

Chapter 13 : Magnetic Effect of Electric Current

Chapter 14 : Sources of Energy

Chapter 15 : Our Environment

Chapter 16 : Management of Natural Resources

Frequently Asked Questions on NCERT Class 10 Chemistry Chapter 2 : Acids, Bases and Salts

Q1. Explain the chemical properties of acids?

Answer:

Reaction of Acid with Metals – Acid when reacted with Metal gives our Hydrogen gas along with the respective salt.

Metal + Acid → Salt + Hydrogen

Reaction of Acid with Metal Carbonate – Acid when reacted with Metal Carbonates gives our Carbon Dioxide gas along with water and respective salt.

Metal carbonate + Acid→ Salt + Carbon dioxide + Water

Reaction of Acid with Hydrogen Carbonates (bicarbonates) – When acids react with metal hydrogen carbonate, they produce carbon dioxide gas, salt, and water.

Acid + Metal hydrogen carbonate→ Salt + Carbon dioxide + Water

Reaction of Acid with Base – When acids and bases react with each other, they produce salt and water.

Acid + Base → Salt + Water

Q2. Why is electricity passed through an acidic aqueous solution?

Answer: The presence of charged particles causes electricity in aqueous acid solutions. The conductivity of electricity in acid solutions is explained by these charged particles known as ions. As electricity is conducted through an aqueous solution of an acid, H+ ions enter the cathode, and each H+ ion takes up one electron from the cathode to generate the H2 gas. This is why electricity is transmitted via an aqueous solution.

Related Chapters

Chapter 1 : Chemical reactions

Chapter 3 : Metals and Non metals

Chapter 4 : Carbon and its compounds

Chapter 5 : Periodic Classification of Elements

Chapter 6 : Life Processes

Chapter 7 : Control and Co-ordination in Plants and Animals

Chapter 8 : Reproduction

Chapter 9 : Heredity and Evolution

Chapter 10 : Light- Reflection and Refaction

Chapter 11 : The Human Eye and colourful World

Chapter 12 : Electricity