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

SCIENCE · Grade 10 · CBSE(NCERT)
Practice Chapter 2: Acids, Bases and Salts with a free chapter-wise online MCQ test. 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

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.