Chapter: Acids, Bases and Salts
Maximum Marks: 40
Time: 1½ Hours
Section A (Objective Type Questions)
(1 × 6 = 6 Marks)
Q.1. Multiple Choice Questions:
(i) The nature of lemon juice is –
(a) Basic (b) Acidic (c) Neutral (d) Salt
(ii) Which of the following is used as an antacid?
(a) NaOH (b) Mg(OH)₂ (c) C₂H₅OH (d) HCl
(iii) Which acid is present in tomato?
(a) Acetic acid (b) Citric acid (c) Tartaric acid (d) Oxalic acid
(iv) A solution turns red litmus blue. Its pH is likely to be –
(a) 1 (b) 4 (c) 5 (d) 10
(v) The chemical formula of Plaster of Paris is –
(a) CaSO₄·2H₂O (b) CaSO₄·½H₂O (c) CaO (d) Na₂CO₃
(vi) Which substance is used for making the drinking water bacteria-free?
(a) Slaked lime (b) Washing soda (c) Bleaching powder (d) Baking soda
Q.2. Fill in the blanks:
(1 × 3 = 3 Marks)
(i) The substances whose taste is sour and turn blue litmus red are called _______.
(ii) _______ is used in hospitals as an antiseptic.
(iii) Acid rain mainly contains _______ acid and _______ acid.
Q.3. One Word Answer:
(1 × 3 = 3 Marks)
(i) Name the acid present in vinegar.
(ii) Which acid is found in ant sting?
(iii) What is the pH value of pure water?
Q.4. Match the following:
(1 × 4 = 4 Marks)
A. Plaster of Paris
B. Gypsum
C. Washing soda
D. Baking powder
- CaSO₄·2H₂O
- Na₂CO₃·10H₂O
- CaSO₄·½H₂O
- Mixture of NaHCO₃ and tartaric acid
Section B (Short Answer Questions)
(2 × 5 = 10 Marks)
Q.5. Why does hydrochloric acid not change the colour of dry litmus paper?
Q.6. State two uses of Plaster of Paris.
Q.7. Write any two uses of washing soda.
Q.8. Write the chemical equation for the preparation of bleaching powder.
Q.9. Why is it recommended to add acid to water and not water to acid?
Section C (Long Answer Questions)
(5 × 2 = 10 Marks)
Q.10. (a) What is pH scale? Explain the importance of pH in everyday life with two examples.
(b) Arrange the following substances in increasing order of hydrogen ion concentration:
(i) Strongly alkaline (pH = 11)
(ii) Neutral (pH = 7)
(iii) Weakly acidic (pH = 4)
(iv) Strongly acidic (pH = 2)
Q.11. (a) What happens when dilute hydrochloric acid reacts with:
(i) Zinc
(ii) Sodium carbonate
(Write balanced chemical equations)
(b) Explain why acid solutions conduct electricity whereas glucose solution does not.
Section D (Very Short Answer Questions)
(2 × 2 = 4 Marks)
Q.12. Name the gas evolved when metal carbonates react with dilute acids. How is it tested?
Q.13. Which substance is used in toothpastes to neutralize excess acid in mouth?
