Question

Which of the following statements explains why a gas fills the container in which it is kept?
(i) The particles in a gas are larger than those in a liquid.

(ii) The particles in a gas have very small attractive forces between them.
(iii) The particles in a gas are constantly moving very quickly.

• A. (i) only
• B. (ii) only
• C. (i) and (ii)
• D. (ii) and (iii)

Answer 1

The correct option is D

(ii) and (iii)

Explanation for the correct answer: (d) (ii) and (iii)

1. Gases have a negligible intermolecular force of attraction between the particles of gas.
2. As a result, the particles of gas is constantly moving in random directions and spread in whole space of the container.
3. So, the gas fills the container in which it is kept

Explanation for the incorrect answers:

(a) (i) only

1. Size of particle totally depends upon the atom from which is made up of.
2. Size of the particle of a substance does not depend on the state of substance in which it exist.

(b) (ii) only

1. The statement ‘The particles in a gas have very small attractive forces between them’ is correct.
2. But the above statement alone does not explains, why a gas fills the container in which it is kept.

(c) (i) and (ii)

1. The statement ‘The particles in a gas are larger than those in a liquid’ is not always true.
2. So, (i) and (ii) can not be the correct explanation.

Thus, option (d) is correct. Gas fills the container in which it is kept because the particles in a gas have very small attractive forces between them and the particles in a gas are constantly moving very quickly.