Acid Base and Salt Mcq

 Acid, Base and Salt MCQ

1. Name the acid present in the following:
(i) Tomato (ii) Vinegar (iii) Tamarind

Answer:- (i) Oxalic acid (ii) Acetic acid (iii) Tartaric acid

2. The pH of an aqueous solution decreases from 3 to 2. What will happen to the nature of the solution ?

Answer: The acidic character of the solution will further increase.

3. What is the chemical name and chemical formula of baking soda ?

Answer: The chemical name of baking soda is sodium hydrogen carbonate or sodium bicarbonate. Its chemical formula is NaHCO₃.

4. Which is a stronger acid ? A solution with pH 5 and a solution with pH 2 ?

Answer: A solution with pH 2 is a stronger acid. In general, lesser the pH, more will be the acidic nature of the solution.

5. Give two examples of the salts belonging to the chloride family.

Answer: Sodium chloride (NaCl) and potassium chloride (KCl).

6. Which bases are called alkalies ? Give an example of alkalies ?

Answer: Water soluble bases are called alkalies. Sodium hydroxide (NaOH) is an example of alkalies.

7. Name the natural source of each of the following :

(a) Citric acid
(b) Oxalic acid
(c) Lactic acid
(d) Tartaric acid. (CBSE 2014)

Answer:
(a) Citrus fruits like lemons and oranges
(b) Tomatoes
(c) Milk
(d) Tamarind.

8. Write the names and chemical formulae of the products formed by heating gypsum at 373 K.

Answer: Gypsum upon heating to 373 K forms Plaster of Paris and water

9. The pH of rain water collected from two cities A and B was found to be 6 and 5 respectively. The water of which city is more acidic ?

Answer: Rain water of city B with pH 5 is more acidic.

10. Why does an aqueous solution of alcohol fail to conduct electric current ?

Answer: An aqueous solution of alcohol fails to conduct electric current since it does not release H+ ions in solution.

11. Name the chemical substance which constitutes bees sting.

Answer: It is methanoic acid or formic acid (HCOOH).

12. Which substance constitutes the enamel coating of our teeth ?

Answer: Calcium phosphate Ca3(PO4)2 constitutes the enamel coating of our teeth.

13. Give examples of two substances having water of crystallisation. Write their formulae also.

Answer: Blue vitriol or hydrated copper sulphate : CuSO4. 5H2O.
Green vitriol or hydrated ferrous sulphate : FeSO4. 7H2O.

14. What are the pH values of distilled water and common salt solution ?

Answer: Both are neutral and have pH close to 7.

1. At what temperature is gypsum heated to form Plaster of Paris?

(a) 90°C
(b) 100°C
(c) 110°C
(d) 120°C
Ans:- (d) 120°C

2. Alkalis are

(a) acids, which are soluble in water
(b) acids, which are insoluble in water
(c) bases, which are insoluble in water
(d) bases, which are soluble in water
Ans:-  (d) bases, which are soluble in water

3. Lime water reacts with chlorine to give

(a) bleaching powder
(b) baking powder
(c) baking soda
(d) washing soda

Answer: c

4. Nettle sting is a natural source of which acid?

(a) MetiWanoic acid
(b) Lactic acid
(c) Citric acid
(d) Tartaric acid

Answer :- a

5. Tooth enamel is made up of

(a) calcium phosphate
(b) calcium carbonate
(c) calcium oxide
(d) potassium

Answer:- a

6. What is the pH range of our body?

(a) 7.0 – 7.8
(b) 7.2 – 8.0
(c) 7.0 – 8.4
(d) 7.2 – 8.4

Answer:- a

7. Rain is called acid rain when its:

(a) pH falls below 7
(b) pH falls below 6
(c) pH falls below 5.6
(d) pH is above 7

Answer :-- c

8. Sodium hydroxide is a

(a) weak base
(b) weak acid
(c) strong base
(d) strong acid

Answer :- c

9. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution would reverse the change?

(a) Baking powder
(b) Lime
(c) Ammonium hydroxide solution
(d) Hydrochloric acid

Answer:- d

10. When copper oxide and dilute hydrochloric acid react, colour changes to

(a) white
(b) bluish-green
(c) blue-black
(d) black

Answer :- b

11. Sodium hydroxide is used

(a) as an antacid
(b) in manufacture of soap
(c) as a cleansing agent
(d) in alkaline batteries

Answer:- b

12. Sodium hydroxide turns phenolphthalein solution

(a) pink
(b) yellow
(c) colourless
(d) orange

Answer :- a

13.  Chemical formula of washing soda is

(a) Na₂C0₃ . 7H₂O
(b) Na₂C0₃ . 5H₂O
(c) Na₂C0₃ . 2H₂O
(d) Na₂C0₃ . 10H₂O

Answer :- d