Acids, Bases and Salts Class 7 Questions

📝 Acids, Bases, and Salts Class 7 Questions

Multiple Choice Questions 

1. The correct way of making a solution of acid in water is to

(a) add water to acid.
(b) add acid to water.
(c) mix acid and water simultaneously.
(d) add water to acid in a shallow container.

Ans: (b)

2. Products of a neutralisation reaction are always

(a) an acid and a base.

(b) an acid and a salt.

(c) salt and water.

(d) a salt and a base.

Ans: (c)

3. Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed

(a) Yellow in both acid and base.

(b) Yellow in acid and red in base.

(c) Pink in acid and yellow in base.

(d) Red in acid and blue in base.

Ans: (b)

4. Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are

(a) red and blue.
(b) blue and red.
(c) pink and colourless.
(d) colourless and pink

Ans: (d)

5. When the soil is too basic, plants do not grow well in it. To improve its quality what must be added to the soil?

(a) Organic matter

(b) Quick lime

(c) Slaked lime

(d) Calamine solution

Ans: (a)

6. ‘Litmus’, a natural dye is an extract of which of the following?

(a) China rose (Gudhal)

(b) Beetroot

(c) Lichen

(d) Blueberries (Jamun)

Ans: (c)

7. Neutralisation reaction is a

(a) physical and reversible change.

(b) a physical change that cannot be reversed.

(c) chemical and reversible change.

(d) the chemical change that cannot be reversed.

Ans: (d)

8. A solution changes the colour of turmeric indicator from yellow to red. The solution is

(a) basic

(b) acidic

(c) neutral

(d) either neutral or acidic

Ans: (a)

9. Which of the following set of substances contain acids?

(a) Grapes, lime water

(b) Vinegar, soap

(c) Curd, milk of magnesia

(d) Curd, vinegar

Ans: (d)

10. On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

(a) Basic

(b) Either acidic or basic

(c) Either acidic or neutral

(d) Either basic or neutral

Ans: (c)

11. Which of the following is an acid-base indicator?

(a) Vinegar

(b) Lime water

(c) Turmeric

(d) Baking soda

Ans: (c)