set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Consider the following statements :

1. The molecules in a gas are in constant motion.
2. Gases have the same pressure throughout the entire atmosphere.
3. Gas molecules are always evenly distributed in the atmosphere.

a) 1 only

b) 1 and 2

c) 2 and 3

d) 2 only

Question : 2

Which one of the following is most electropositive element?

a) Calcium

b) Aluminium

c) Sodium

d) Silicon

Question : 3

Which of the following elements A, B, C, D and E with atomic number 3, 11, 15, 18 and 19 respectively belong to the same group?

a) B, C, D

b) A, D, E

c) A, B, C

d) A, B, E

Question : 4

Consider the following statements :

1. The rate of evaporation depends only on the surface area exposed to the atmosphere.
2. Latent heat of vaporisation is the heat energy required to change 1 kg of a liquid to gas at atmospheric pressure at its melting point.

a) 1 and 2 both

b) 1 only

c) 2 only

d) None

Question : 5

Consider the following statements :

1. Living beings carry out their metabolic activities with in an optimal pH range.
2. There are a variety of strengths when you study acids and base.

a) 1 and 2 both

b) 1 only

c) 2 only

d) None

Question : 6

Which of the following statements about pH and $H^+$ ion concentration are incorrect?

1. Addition of one drop of concentrated HCl in NH₄OH solution decreases pH of the solution.
2. A solution of the mixture of one equivalent of each of CH₃COOH and NaOH has a pH of 7
3. pH of pure neutral water is not zero
4. A cold and concentrated H₂SO₄ has lower $H^+$ ion concentration than a dilute solution of H₂SO₄

a) 1, 2 and 4

b) 1, 2 and 3

c) 1, 3 and 4

d) 2, 3 and 4