Chapter Exam

Chapter 2: Acids, Bases and Salts — Online MCQ Test

Q: What colour does red litmus paper turn in the presence of a base?

Answer: C. Blue — Red litmus paper turns blue in the presence of a base, which is a key property used to identify basic solutions.

Q: Which gas is liberated when an acid reacts with a metal?

Answer: D. Hydrogen — When an acid reacts with a metal, hydrogen gas is liberated along with a salt.

Q: A solution has a pH of 10. Which of the following best describes this solution?

Answer: D. Basic — A pH of 10 is greater than 7, which indicates a basic solution. It also turns red litmus paper blue.

Q: Arrange the following pH values in increasing order of hydrogen ion concentration: 11, 9, 7, 4, 1.

Answer: B. 11 < 9 < 7 < 4 < 1 — pH is inversely related to hydrogen ion concentration. As pH decreases, H+ concentration increases. So order of increasing H+ concentration is pH 11 < 9 < 7 < 4 < 1.

Q: Which of the following best explains why concentrated sulfuric acid is a strong dehydrating agent while dilute sulfuric acid is not?

Answer: B. Concentrated H2SO4 has high affinity for water and removes it from substances, while dilute form is diluted with water — Concentrated H2SO4 absorbs water strongly due to high affinity; addition to water is highly exothermic. Dilute H2SO4 already contains water, so it cannot dehydrate.

SCIENCE · Grade 10 · CBSE(NCERT)

Practice Chapter 2: Acids, Bases and Salts with a free chapter-wise online MCQ test for CBSE(NCERT) Grade 10 SCIENCE. This chapter covers: chemistry-2. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 2: Acids, Bases and Salts — Important Questions & Answers (FAQ)

Frequently asked questions from CBSE(NCERT) Grade 10 SCIENCE — Chapter 2: Acids, Bases and Salts, with answers and explanations. These are sample questions; the exam has its own separate question set.

What colour does red litmus paper turn in the presence of a base?

A. Yellow
B. Green
C. Blue ✓
D. Remains red

Answer: C. Blue
Red litmus paper turns blue in the presence of a base, which is a key property used to identify basic solutions.

Which gas is liberated when an acid reacts with a metal?

A. Oxygen
B. Carbon dioxide
C. Nitrogen
D. Hydrogen ✓

Answer: D. Hydrogen
When an acid reacts with a metal, hydrogen gas is liberated along with a salt.

A solution has a pH of 10. Which of the following best describes this solution?

A. Strongly acidic
B. Weakly acidic
C. Neutral
D. Basic ✓

Answer: D. Basic
A pH of 10 is greater than 7, which indicates a basic solution. It also turns red litmus paper blue.

Arrange the following pH values in increasing order of hydrogen ion concentration: 11, 9, 7, 4, 1.

A. 1 < 4 < 7 < 9 < 11
B. 11 < 9 < 7 < 4 < 1 ✓
C. 7 < 4 < 1 < 9 < 11
D. 4 < 1 < 7 < 9 < 11

Answer: B. 11 < 9 < 7 < 4 < 1
pH is inversely related to hydrogen ion concentration. As pH decreases, H+ concentration increases. So order of increasing H+ concentration is pH 11 < 9 < 7 < 4 < 1.

Which of the following best explains why concentrated sulfuric acid is a strong dehydrating agent while dilute sulfuric acid is not?

A. Concentration determines acid strength, not dehydrating ability
B. Concentrated H2SO4 has high affinity for water and removes it from substances, while dilute form is diluted with water ✓
C. Dilute H2SO4 is a weak acid and cannot remove water
D. Only concentrated acids show exothermic reactions with water

Answer: B. Concentrated H2SO4 has high affinity for water and removes it from substances, while dilute form is diluted with water
Concentrated H2SO4 absorbs water strongly due to high affinity; addition to water is highly exothermic. Dilute H2SO4 already contains water, so it cannot dehydrate.