Question

The molecules of a gas are in constant ________ (i) _______ motion. They move in _____ (ii) ______ lines until they collide with another molecule. The collisions are perfectly ____ (iii) ____ in nature. A real gas behaves as an ideal gas at ______ (iv) ____ temperature and _____ (v) _____ pressure.
(a)- Random, vertical, straight, high, low.
(b)- Straight, random, elastic, low, high
(c)- Random, straight, elastic, high, low
(d)- Ideal, round, elastic, low, high

Answer 1

Hint: It is based on the theory of the Brownian movement or Brownian motion of particles. When the pressure is low and high temperature only the real gas behaves as an ideal gas.

Complete answer:
Based on Brownian movement or Brownian motion of particles:
The molecules of a gas are in constant random motion. They move in straight lines until they are colloid with another molecule. The collisions are perfectly elastic in nature. A real gas behaves as an ideal gas at high temperature and low pressure.
The Brownian movement may be defined as the continuous zig-zag movement of the particles.
The cause of the Brownian movement is the fact that the molecules in the dispersion medium due to their kinetic motion strike against the colloidal particles from all sides with different forces. The resultant force causes them to move.
When the pressure is low and high temperature only the real gas behaves as an ideal gas.
So, the correct answer is “Option C”.

Note: It is due to the Brownian movement the particles are in constant movement and do not settle down. The Brownian movement opposes the force of gravity.