9th class Chemistry, Chapter 7: Acid Base Chemistry MCQs

1. Which acid is not used as a food or mixed with food?

1. (A) Tartaric acid
2. (B) Ascorbic acid
3. (C) Citric acid
4. (D) Formic acid ✓

2. While baking, which gas is responsible for raising the bread and making it soft?

1. (A) Oxygen
2. (B) Carbon dioxide ✓
3. (C) Nitrogen
4. (D) Carbon monoxide

3. Predict the main characteristics of the reactions of metals with acids.

1. (A) Metals are dissolved
2. (B) Metals are converted into salts
3. (C) Hydrogen gas is evolved
4. (D) All the above mentioned characteristics are true ✓

4. How many hydroxide ions, calcium hydroxide will release in water?

1. (A) 1
2. (B) 2 ✓
3. (C) Zero
4. (D) 3

5. In a neutralization reaction between KOH and H₃PO₄, how many molecules of KOH will react with one molecule of H₃PO₄?

1. (A) 2
2. (B) 1
3. (C) 3 ✓
4. (D) 4

6. Which acid is used in the preparation of soap?

1. (A) Tartaric acid
2. (B) Citric acid
3. (C) Stearic acid ✓
4. (D) Oxalic acid

7. Which compound is formed when SO₂ is dissolved in water?

1. (A) SO₃
2. (B) H₂SO₃ ✓
3. (C) H₂SO₄
4. (D) H₂S₂O₇

8. Which of the following contains oxalic acid?

1. (A) Tomato ✓
2. (B) Orange
3. (C) Tamarind
4. (D) Sour milk

9. Which compound in the following reaction is behaving as a conjugate base? CH₃COOH(aq) + H₂O(l) → CH₃COO⁻(aq) + H₃O⁺(aq)

1. (A) CH₃COOH
2. (B) H₂O
3. (C) CH₃COO⁻ ✓
4. (D) H₃O⁺

10. When a chemical reaction is carried out with a substance Z; a gas is produced which turns red litmus paper blue. What is the reaction?

1. (A) Reaction of an acid with a metal carbonate
2. (B) Reaction of an acid with metal hydrogen carbonate
3. (C) Reaction of an alkali with an acid
4. (D) Reaction of an alkali with ammonium salt ✓

11. Acids change the colour of litmus paper from:

1. (A) Red to colourless
2. (B) Blue to green
3. (C) Blue to red ✓
4. (D) Red to blue

12. Acids obtained from natural sources are called:

1. (A) Man-made acids
2. (B) Organic acids ✓
3. (C) Mineral acids
4. (D) Strong acids

13. Which of the following is a mineral acid?

1. (A) Nitric acid ✓
2. (B) Citric acid
3. (C) Lactic acid
4. (D) Acetic acid

14. Ascorbic acid is found in:

1. (A) Amla and guava ✓
2. (B) Vinegar
3. (C) Tomato
4. (D) Ant sting

15. Lactic acid is found in:

1. (A) Tamarind
2. (B) Vinegar
3. (C) Sour milk and curd ✓
4. (D) Lemon

16. Tartaric acid is obtained from:

1. (A) Tamarind ✓
2. (B) Tomato
3. (C) Orange
4. (D) Curd

17. Caustic soda is the common name of:

1. (A) Potassium hydroxide
2. (B) Calcium hydroxide
3. (C) Sodium carbonate
4. (D) Sodium hydroxide ✓

18. A base that dissolves in water is called a/an:

1. (A) Salt
2. (B) Acid
3. (C) Oxide
4. (D) Alkali ✓

19. Na₂O is a basic oxide; with water it forms:

1. (A) NaOH ✓
2. (B) Na₂CO₃
3. (C) NaCl
4. (D) Na₂O₂

20. The simplest organic diprotic acid is:

1. (A) Acetic acid
2. (B) Citric acid
3. (C) Oxalic acid (H₂C₂O₄) ✓
4. (D) Formic acid