Chemistry Class 10: Acids, Bases, and Salts

Chemistry Class 10 Chapter 2: Acids, Bases, and Salts

Introduction

In this chapter, we will explore the properties and behavior of acids, bases, and salts. These substances play a crucial role in various aspects of our daily life, from cleaning to cooking, and even in the functioning of our bodies. Let's delve deeper into the world of acids, bases, and salts.

Acids

An acid is a substance that donates a proton (H+) when dissolved in water. Acids can be found in various forms, such as hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), and acetic acid (CH3COOH). Some common characteristics of acids include:

1. Sour taste
2. Formation of hydronium ions (protons) when dissolved in water
3. Reaction with bases, leading to neutralization

Bases

A base is a substance that accepts a proton (OH-) when dissolved in water. Bases can be found in substances like sodium hydroxide (NaOH), calcium hydroxide (Ca(OH)2), potassium hydroxide (KOH), and ammonia (NH4OH). Common characteristics of bases include:

1. Bitter taste and soapy feel
2. Formation of hydroxide ions (OH-) when dissolved in water
3. Reaction with acids, leading to neutralization

Salts

A salt is an ionic compound formed when a hydrogen ion (H+) is replaced by a positive ion (e.g., Na+, K+, or NH4+) in an acid. Salts can be formed from the reaction between acids and bases, and they are composed of positive ions (cations) of bases and negative ions (anions) of acids. Some common characteristics of salts include:

1. Neutral taste and appearance
2. Formation of ions when dissolved in water
3. No net charge or acidic/basic properties

Neutralization Reactions

When an acid and a base are mixed in the correct proportions, a neutralization reaction occurs, resulting in the formation of a salt and water. The general chemical equation for a neutralization reaction is:

$$Base + Acid \rightarrow Salt + Water$$

For example, when hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), the following reaction takes place:

$$NaOH + HCl \rightarrow NaCl + H_2O$$

Acid-Base Properties of Some Common Substances

Many substances we encounter in our daily lives are acids or bases. Some examples include:

1. Acids: Vinegar (acetic acid), lemon juice (citric acid), and tartaric acid (found in tamarind) are examples of acids.
2. Bases: Lime water, ammonia, and base (OH-) salts are examples of bases.

Important Terms and Concepts

1. Arrhenius Theory: The theory that classifies acids and bases based on their properties.
2. Homogeneous Solution: A solution in which the solute is evenly spread out and has the same properties throughout the solution.
3. Molarity: The number of moles of solute per liter of solution.
4. Concentration: The amount of solute per liter of solution, measured in molarity or percentage by mass.
5. pH: A scale that ranges from 0 to 14, where 0 indicates a strong acid, and 14 indicates a strong base.
6. pOH: A scale that ranges from 0 to 14, where 0 indicates a strong base, and 14 indicates a strong acid.

Conclusion

In this chapter, we learned about the properties and behavior of acids, bases, and salts. We explored the neutralization reactions that occur when acids and bases are mixed and the importance of understanding the acid-base properties of common substances. As we progress further in our studies of chemistry, we will delve deeper into the mechanisms and reactions of these versatile substances.