Write true or false for each statement :

(a) The molecules of each substance are identical.

(b) The inter-molecular forces are effective at all distances between the two molecules.

(c) The molecules in a substance are in random motion.

(d) In a gas, the molecules can move anywhere in space.

(e) Liquids are less viscous than gases.

(a) False because different substances (e.g. air, water etc.) contain different types of molecules, so they are not identical

(b) False as intermolecular forces act only at very short distances (a few nanometers). At large distances, they become negligible.

(c) True since the particles of matter are not at rest, but they move randomly in all possible directions in a zig zag path.

(d) True as the inter-molecular forces are very weak in a gas which makes the molecules wide apart and hence, they can move freely in space.

(e) False because liquids are generally more viscous than gases because their molecules are closer together, leading to more friction between different layers.