Vardaan Learning Institute

Topic: Acids, Bases and Salts

Class: 10 (Science) Type: Bonus Practice Paper Max. Marks: 50
Name:
Date:
SECTION A: OBJECTIVE TYPE QUESTIONS (1 Mark Each)
1. Which one of the following salts does not contain water of crystallisation?
  1. Blue vitriol
  2. Baking soda
  3. Washing soda
  4. Gypsum
2. Sodium carbonate is a basic salt because it is a salt of:
  1. strong acid and strong base
  2. weak acid and weak base
  3. strong acid and weak base
  4. weak acid and strong base
3. Calcium phosphate is present in tooth enamel. Its nature is:
  1. Basic
  2. Acidic
  3. Neutral
  4. Amphoteric
4. A solution turns red litmus blue, its pH is likely to be:
  1. 1
  2. 4
  3. 5
  4. 10
5. Which of the following statements is correct about an aqueous solution of an acid and of a base?
  1. Higher the pH, stronger the acid
  2. Higher the pH, weaker the acid
  3. Lower the pH, stronger the base
  4. Lower the pH, weaker the base
  1. (i) and (iii)
  2. (ii) and (iii)
  3. (i) and (iv)
  4. (ii) and (iv)
6. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains:
  1. $NaCl$
  2. $HCl$
  3. $LiCl$
  4. $KCl$
7. Which of the following medicines is used for treating indigestion?
  1. Antibiotic
  2. Analgesic
  3. Antacid
  4. Antiseptic
8. When copper oxide and dilute hydrochloric acid react, colour changes to:
  1. White
  2. Bluish-green
  3. Blue-black
  4. Black
9. Sodium hydroxide is a:
  1. Weak base
  2. Weak acid
  3. Strong base
  4. Strong acid
10. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?
  1. Baking powder
  2. Lime
  3. Ammonium hydroxide solution
  4. Hydrochloric acid
Directions (Q11-Q14): In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
  1. Both A and R are true and R is the correct explanation of A.
  2. Both A and R are true but R is not the correct explanation of A.
  3. A is true but R is false.
  4. A is false but R is true.
11. Assertion (A): The pH of ammonium chloride solution is less than 7.
Reason (R): Ammonium chloride is a salt of a weak acid and a strong base.
12. Assertion (A): Antacids are used to relieve indigestion.
Reason (R): Antacids contain weak acids that neutralize the effect of excess base in stomach.
13. Assertion (A): $HCl$ gas changes the colour of dry blue litmus paper.
Reason (R): Acids show acidic behaviour in the absence of water.
14. Assertion (A): Plaster of Paris should be stored in a moisture-proof container.
Reason (R): Plaster of Paris sets into a hard mass on wetting with water.
SECTION B: SHORT ANSWER QUESTIONS (3 Marks Each)
15. (i) Write the chemical name and formula of bleaching powder.
(ii) Why does bleaching powder smell strongly of chlorine?
(iii) State one industrial use of bleaching powder.
16. What is 'water of crystallisation'? State the number of water molecules of crystallisation in:
(i) Green vitriol
(ii) Washing soda
(iii) Plaster of Paris
17. (i) Three acidic solutions A, B and C have pH = 0, 3 and 5 respectively. Which solution has highest concentration of $H^+$ ions?
(ii) Which acid is produced in our stomach? What happens if there is an excess of acid in the stomach? How can its effect be cured?
18. Draw a neat labelled diagram of the apparatus used for passing current through acid solution. (Diagram is not required to be drawn here, student to draw).
19. Explain why:
(a) An aqueous solution of an acid conducts electricity.
(b) Sour substances like curd should not be kept in brass vessels.
(c) Tap water conducts electricity whereas distilled water does not.
20. What is meant by 'Family of salts'? State the family to which the following salts belong:
(i) Potassium Sulphate
(ii) Sodium Sulphate
(iii) Sodium Chloride
(iv) Ammonium Chloride
SECTION C: LONG ANSWER QUESTIONS (5 Marks Each)
21. (i) The Ph of soil A is 7.5 while that of soil B is 4.5. Which of the two soils should be treated with powdered chalk to adjust its pH and why?
(ii) Explain how the pH change in the river water can endanger the lives of aquatic animals.
(iii) What is the chemical formula of Plaster of Paris? How is it prepared? Write the chemical equation. Why should it be stored in a moisture-proof container?
22. (i) Write the chemical name and formula of washing soda. How is it obtained from sodium chloride? Give equations of reactions involved.
(ii) State two uses of washing soda.
SECTION D: CASE STUDY (4 Marks)
23. Read the following text and answer the questions:
The pH of a solution is a measure of its hydrogen ion ($H^+$) concentration. It is a scale used to specify the acidity or basicity of an aqueous solution. The pH scale ranges from 0 to 14. A solution with a pH less than 7 is acidic, while a solution with a pH greater than 7 is basic. A solution with a pH of 7 is neutral.

A student tested the pH of distilled water and found it to be 7. He then added a few drops of common salt (NaCl) solution to it.

(i) What will be the nature of the salt solution: acidic, basic or neutral? (1 Mark)
(ii) If he adds a few drops of universal indicator to the salt solution, what colour will it show? (1 Mark)
(iii) Explain why the pH of an acid rain sample is less than 5.6. (2 Marks)
24. Read the following text and answer the questions:
Common salt, which we use in food, is an important raw material for various materials of daily use, such as sodium hydroxide, baking soda, washing soda, bleaching powder and many more. The chemical name of common salt is Sodium Chloride ($NaCl$).

(i) Which process is used to prepare Sodium Hydroxide from Sodium Chloride? (1 Mark)
(ii) Write the chemical formula of Baking Soda. (1 Mark)
(iii) Write the chemical reaction involved in the preparation of Bleaching Powder. (2 Marks)
"All the best!"