Chapter 2

Acids, Bases, and Salts

Introduction

Welcome to Chapter 2 of Chemistry for Class 10. This chapter explores the properties, reactions, and applications of acids, bases, and salts, fundamental substances in chemistry.

Acids

Definition

Acids are substances that donate protons (H+) when dissolved in water, leading to the formation of hydronium ions (H3O+).

Properties

  • Sour taste and corrosive nature.
  • Turn blue litmus paper red.
  • React with metals to release hydrogen gas.

Types of Acids

  • Mineral Acids: Strong acids like hydrochloric acid (HCl), sulfuric acid (H2SO4).
  • Organic Acids: Found in foods and natural substances (e.g., citric acid in fruits).

Bases

Definition

Bases are substances that accept protons (H+) when dissolved in water, leading to the formation of hydroxide ions (OH−).

Properties

  • Bitter taste and slippery feel.
  • Turn red litmus paper blue.
  • Are electrolytes and conduct electricity in aqueous solutions.

Types of Bases

  • Alkalis: Soluble bases like sodium hydroxide (NaOH), potassium hydroxide (KOH).
  • Non-Alkalis: Insoluble bases like magnesium hydroxide (Mg(OH)2).

Salts

Definition

Salts are ionic compounds formed by the neutralization reaction between an acid and a base.

Properties

  • Composed of positively charged ions (cations) and negatively charged ions (anions).
  • Are electrolytes and conduct electricity when dissolved in water.

Types of Salts

  • Normal Salts: Formed by complete neutralization of acids and bases.
  • Acidic Salts: Formed when only a part of the replaceable hydrogen atoms of the acid are replaced.
  • Basic Salts: Formed when all the hydrogen atoms of the acid are not replaced.

pH Scale

Definition

The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14.

  • Acidic Solutions: pH less than 7.
  • Neutral Solutions: pH equal to 7 (e.g., pure water).
  • Basic Solutions: pH greater than 7.

Applications of Acids, Bases, and Salts

Industrial Applications

  • Production of fertilizers (e.g., ammonium sulfate).
  • Manufacturing of soap and detergents.
  • Preservation of food (e.g., pickling).

Household Applications

  • Cleaning agents (e.g., vinegar, baking soda).
  • Personal care products (e.g., toothpaste).
  • Medical uses (e.g., antacids).

Conclusion

Understanding acids, bases, and salts is crucial in chemistry as they play vital roles in various applications from industrial processes to everyday household products. Mastering their properties, reactions, and applications enhances our understanding of chemical interactions and their impact on our lives.

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