NCERT Class 10 Science Chapter 2 Notes Acids, Bases, and Salts- Download PDF Notes

Class 10 Science Chapter 2 notes provide an overview of the important concepts such as acids, bases, their properties, types of indicators, and their characteristics. These notes cover the behavior and properties of acids, bases, and salts along with explaining their reactions in aqueous solutions and the factors which determine their strength.

Along with this, notes provided here discuss the principles and techniques for preparing common salts. Students can download the chemistry class 10 chapter 2 CBSE Notes PDF free of charge for effective exam preparation.

NCERT Class 10 Chapter 2 Notes

Understanding the Chemical Properties of Acids and Bases

Concept of Acids

Taste of acids: Sour

Change in colour: Acids change their colour from blue to red while performing a litmus test.

Concept of Bases

Taste of acids: bitter

Change in colour: Bases change their colour from red to blue while performing a litmus test.

Litmus: This can be extracted from lichen and is a purple dye solution.

It is the fact that if the litmus is neither acidic nor basic in nature, then it shows a purple colour.

Indication of acid and base inside any material:

Natural materials like:

• Red cabbage leaves

• Turmeric

• Coloured petals of flowers such as Petunia, Geranium, etc.

Properties of Acids and Bases

Acids

The word is derived from the Latin word called “acidus”.

When dissolved in an aqueous medium, it gives hydrogen ions to the solution.

Concentrated acids are mixtures of a larger amount of acid dissolved in a smaller amount of water.

Dilute acids are mixtures of a larger amount of water dissolved in a smaller amount of acids.

Examples of strong acids: are HCl, H₂SO₄, HNO₃, etc.

Examples of weak acids: are CH₃COOH, Lactic acid, oxalic acid, etc.

Bases

The substances which are basic in nature are soapy in touch.

When dissolved in an aqueous medium, it gives hydroxide ions in the solution.

Alkali is the base that is soluble in water. Examples of alkali are NaOH, KOH, etc.

Examples of strong bases: NaOH, KOH, Ca(OH)₂

Example of weak bases: NH₄OH

Indicators

Indicators are defined as changes in the colour or smell of a substance in different types of acids and bases.

Types of indicators are as follows:

1. Natural indicators

2. Synthetic Indicators

3. Olfactory indicators

Reactions of Acids and Bases When Reacted with Metals

• The reaction of Acids with Metals produces salt and hydrogen gas.

Acid + Metal Salt + Hydrogen gas

Example of such reaction: Zn+2HCl→ZnCl₂+H₂

• The reaction of Bases when reacting with Metals produces salt and hydrogen gas.

The base, which is reacting with metal, has to be more reactive than the base.

But all the metals do not have the nature to react with bases.

Base + metal → salt + Hydrogen gas

Example of such reaction: 2NaOH+Zn→Na₂ZnO₂ + H₂

The evolved hydrogen gas burned with a pop sound when it came closer to the evolved gas.

• The reaction of acids when reacting with carbonates and hydrogen carbonates

Reaction of acid with metal carbonates and hydrogen carbonates

Reaction of acid with metal caronates nad hydrogen carbonates

Acid + Metal carbonates or hydrogen carbonates $⟶$ Salt +Water +Carbon dioxide

$\mathrm{HCl}+{\mathrm{NaHCO}}_3⟶\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

The produced carbon dioxide will be further tested and passed through lime water solution, which turns the solution milky. But it should be noticeable that the amount of carbon dioxide is certain, if it passes in excess amount then the milkiness will disappear.

Reaction when the amount of carbon dioxide is certain.

Reaction when amount of carbon dioxide is in excess.

The reaction of bases when reacting with carbonates and hydrogen carbonates

No such reaction will proceed when the base reacts with metal carbonate and metal hydrogen carbonates.

• The reaction of acids and bases with each other

When acids and bases react with each other they produce salt and water, such reaction is termed a

termed a neutralisation reaction.

• Strong acid+ weak base gives acidic salt and water.

• Weak acid+ strong base gives acidic salt and water.

• Strong acid+ strong base gives neutral salt and water.

• Weak acid+ weak base gives neutral salt and water.

• The reaction of acids when reacted with metallic oxides

The nature of metallic oxides is basic.

• The reaction of acids when reacted with non-metallic oxides

The nature of metallic oxides are acidic.

Similarities Between Acids and Bases

Acids and bases have some similarities in between them and they are listed below:

• Acids give hydrogen ions when dissolve in any solution, so the common ion is hydrogen ion, which makes any mixture acidic in nature.

• Bases give hydroxide ions when dissolved in any solution, so the common ion is hydroxide ion, which makes any mixture basic in nature.

Water solution with acids or bases:

When acids dissolve in water, they produce hydrogen ions, but hydrogen ion cannot exist alone they exist in the form of hydronium ion.

When bases dissolve in water, they give hydroxide ions.

Bases that are soluble in water are termed alkali.

Point to remember: When we are diluting any acid to water, it should be kept in mind that acid must be added to water, not the water to acid, as the process of dissolving any acid or base is highly exothermic in nature.

Strength of Acids and Base Solution

This can be evaluated by an indicator known as a universal indicator.

Universal indicator: This indicator is a mixture of different indicators which shows colour when any solution concentration has hydrogen ion or hydroxide ion in it.

pH scale: For measuring the concentration of hydrogen ion in any solution, that how acidic or basic the solution, we must require a scale that scale is termed as pH scale. p in pH denotes potenz which in general means power.

Neutral, Acidic and Basic Salts

The salts that are produced by strong acid and strong bases are neutral in nature. The pH value of such a salt is 7.

Formation of Sodium Chloride

Formation of Sodium Hydroxide

Formation of Bleaching Powder

Bleaching powder

$\underset{\begin{array}{c}\mathrm{Ca}(\mathrm{OH}{)}_2\\ \text{ slaked lime }\end{array}}{\mathrm{Cl}}{\mathrm{Cl}}_2⟶\underset{\text{ Bleaching powder }}{{\mathrm{CaOCl}}_2}+{\mathrm{H}}_2\mathrm{O}$

Formation of Baking Powder

Formation of Baking Soda

$\underset{\text{ Baking soda }}{{\mathrm{NaHCO}}_3}+\underset{\text{ tartric acid }}{\mathrm{CHO}}⟶{\mathrm{CO}}_2+{\mathrm{H}}_2\mathrm{O}+{\mathrm{Na}}_2{\mathrm{C}}_4{\mathrm{H}}_4{\mathrm{O}}_6$

Chapter wise NCERT class 10 Notes Science

Significance of NCERT Class 10 Science Chapter 2 Notes

The NCERT notes class 10 science chapter 2 acids, bases and salts provide a precise and structured revision of the entire chapter in a single NCERT class 10 science chapter 2 notes pdf, eliminating the need for students to search for additional resources. In this article, we have provided a step-by-step analysis of the topic, which will help students get more clarity on the topics and it will further make the revision effective.

The acids, bases and salts class 10 short notes provided here cover all the topics of the chapter in a detailed manner. Topics such as the behavior of acids, bases, and salts, their properties, and their reactions with different compounds are discussed in depth. The notes provided here are a good source to revise, also students can download the PDF to study offline. Also, these notes help understand the key concepts mentioned in CBSE Class 10 Science Syllabus, which ensures an effective learning experience.

Also, students can refer to:

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