NCERT Exemplar Solution for Class 10 Science Chapter-2 Acids, Bases and Salts
Acids, bases, and salts are among the most interesting topics in chemistry because they are closely connected to everyday life. From the sour taste of lemon juice to the use of soap, toothpaste, and baking soda, this chapter explains the science behind many common substances. Chapter 2 helps students understand the chemical nature of acids and bases, their reactions, and the role of indicators in identifying them. It also introduces important industrial products such as bleaching powder, baking soda, washing soda, and plaster of Paris. Students often rely on NCERT Exemplar Solution for Class 10 Science, NCERT Exemplar Solution, and NCERT solutions for class 10 to gain better conceptual clarity and improve problem-solving skills in this chapter.
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Understanding Acids and Bases
The chapter begins with the basic properties of acids and bases. Acids are substances that produce hydrogen ions in aqueous solutions, while bases release hydroxide ions. Acids usually have a sour taste, whereas bases are bitter and feel soapy. Since tasting chemicals is unsafe, indicators are used to identify them in laboratories.
Indicators such as litmus, methyl orange, and phenolphthalein help determine whether a substance is acidic or basic. Natural indicators like turmeric and china rose are also discussed. These indicators change color depending on the nature of the solution, making experiments more interesting and easier to understand. One of the key concepts explained in the chapter is the reaction of acids and bases with metals. When acids react with metals, hydrogen gas is produced along with a salt. Bases also react with certain metals like zinc and aluminum to release hydrogen gas. Students also learn about neutralization reactions, where acids and bases react together to form salt and water.
The role of water in acid-base behavior is another important topic. Acids and bases show their properties only in aqueous solutions because ions are produced in the presence of water. This helps students understand why dry hydrogen chloride gas does not change the color of dry litmus paper.
Strength of Acids, pH Scale, and Chemical Reactions
The chapter introduces the pH scale, which measures how acidic or basic a solution is. The pH scale ranges from 0 to 14. Solutions with a pH less than 7 are acidic, while those above 7 are basic. A pH value of 7 represents a neutral solution.
Understanding the pH scale is important because it explains many natural and biological processes. For example, the human digestive system contains hydrochloric acid, which helps in digestion. Tooth decay occurs when the pH inside the mouth falls below a certain level. Farmers also use pH testing to check soil conditions for healthy crop growth. Students learn that acids react with metal carbonates and metal hydrogen carbonates to produce carbon dioxide gas, salt, and water. These reactions are commonly observed in laboratory experiments and examination questions. The chapter also explains why antacids are used to neutralize excess acid in the stomach.
Another important concept is the difference between strong and weak acids or bases. Strong acids ionize completely in water, while weak acids ionize partially. Similar behavior is observed in bases. These concepts help students understand conductivity and chemical reactivity more clearly.
Important Salts and Their Uses
This chapter also covers the preparation and uses of important salts. Common salt, or sodium chloride, is one of the most useful compounds discussed in the lesson. It is not only used in food but also acts as a raw material for many industrial chemicals.
The chlor-alkali process explains how sodium hydroxide, chlorine, and hydrogen gas are produced from brine. Students also study bleaching powder, which is widely used for disinfecting drinking water and bleaching fabrics. Baking soda is another useful compound used in cooking and fire extinguishers. Washing soda is discussed as a cleaning agent and water softener. The chapter further explains the preparation and uses of plaster of Paris, which is commonly used for making statues, toys, and medical casts for fractured bones. NCERT exemplar exercises based on these topics help students understand practical applications of chemistry. The questions are designed to improve logical thinking and scientific reasoning. Regular practice strengthens confidence and helps students answer both theoretical and application-based questions effectively.
The chapter also emphasizes laboratory safety and careful observation during experiments. Students learn how chemistry is connected to daily life and industrial processes. By studying reactions, formulas, and applications together, learners develop a deeper understanding of the subject.