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Chapter Analysis
Intermediate19 pages • EnglishQuick Summary
Chapter 2 of the Class 10 Science textbook on 'Acids, Bases and Salts' explores the chemical properties and reactions of acids and bases. It discusses the concept of pH, highlighting how acids and bases affect their environment, including everyday materials and biological systems. The chapter elaborates on the neutralization process, the role of indicators, and the industrial applications of salts derived from these reactions.
Key Topics
- •Acid and Base Indicators
- •Properties of Acids and Bases
- •Neutralization Reaction
- •pH and its Importance
- •Industrial Application of Salts
- •Reaction of Acids with Metals
- •Difference between Strong and Weak Acids
- •Water of Crystallization and its Uses
Learning Objectives
- ✓Identify and explain the properties of acids and bases.
- ✓Understand the concept of pH and its significance.
- ✓Describe the process of neutralization and its applications.
- ✓Recognize the industrial importance of salts.
- ✓Differentiate between strong and weak acids and bases.
- ✓Explain the role of water in the acidic or basic nature of compounds.
Questions in Chapter
Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Page 26
Why does an aqueous solution of an acid conduct electricity?
Page 26
Why does dry HCl gas not change the colour of the dry litmus paper?
Page 26
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Page 26
How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted?
Page 26
How is the concentration of hydroxide ions (OH–) affected when excess base is dissolved in a solution of sodium hydroxide?
Page 26
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.
Page 35
Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it.
Page 35
Why does distilled water not conduct electricity, whereas rain water does?
Page 35
Why do acids not show acidic behaviour in the absence of water?
Page 35
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 (a) neutral? (b) strongly alkaline? (c) strongly acidic? (d) weakly acidic? (e) weakly alkaline? Arrange the pH in increasing order of hydrogen-ion concentration.
Page 35
Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) 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?
Page 35
Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.
Page 35
A milkman adds a very small amount of baking soda to fresh milk. (a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline? (b) Why does this milk take a long time to set as curd?
Page 35
Plaster of Paris should be stored in a moisture-proof container. Explain why?
Page 35
What is a neutralisation reaction? Give two examples.
Page 35
Additional Practice Questions
Explain how the pH scale is related to the strength of acids and bases.
mediumAnswer: The pH scale ranges from 0 to 14, determining how acidic or basic a solution is. A pH of 7 is neutral, values less than 7 indicate acidity, and values greater than 7 indicate alkalinity. The strength of an acid or base corresponds to its ability to dissociate in water and the concentration of hydrogen (H+) or hydroxide (OH-) ions it produces.
Describe the process and purpose of a neutralization reaction.
easyAnswer: A neutralization reaction involves the reaction of an acid and a base to produce a salt and water. It is used to balance pH in various applications, such as relieving indigestion, treating acidic or alkaline soil, or wastewater treatment.
What role do indicators play in determining the pH of a solution?
easyAnswer: Indicators change color to signify whether a solution is acidic or basic. For example, litmus changes from blue to red in acid and from red to blue in a base. Such indicators are valuable tools in laboratory experiments to quickly assess the nature of a solution.
Why is it important to add acid to water rather than water to acid during dilution?
hardAnswer: Adding acid to water is recommended because it disperses the acid molecules more evenly, reducing the exothermic reaction's intensity and preventing the mixture from spattering.
Discuss the industrial applications of salts derived from acids and bases.
mediumAnswer: Salts have a wide range of industrial applications. Sodium chloride is essential in the chemical industry, sodium carbonate is used in glass manufacturing, and calcium sulfate is used in construction. Salts also find use in food preservation, tanning, and agriculture.
NCERT Exemplar
AvailablePractice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.
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