Question

Why is the rate of diffusion of liquids higher than that of solids?
A) Solids have higher inter-particle space than liquids.
B) Liquids have higher inter-particle space than solids.
C) Solids have higher inter-particle space than gas.
D) None of these.

Answer 1

The rate of diffusion refers to the amount of material diffused in unit time. We can express the amount in terms of number of moles, mass or volume. We can express the time in terms of seconds, minutes, hours or sometimes days.

Complete answer:
There are three phases of matter. These include solid, liquid and gas. The interparticle space increases in the order solid < liquid < gas.
Solids have tightly packed crystal lattices. In solid, the particles are very close to each other and the interparticle space is very small. Due to this, the free movement of solids is restricted and the rate of diffusion of solids is very small, almost negligible.
On the other hand, liquids have a loosely packed arrangement of particles. In liquid, the particles are somewhat close to each other and the interparticle space is comparatively large. Due to this, the free movement of liquids is possible and the rate of diffusion of liquids is large.
When interparticle space is high for liquids, the fluidity is also high. Due to this, the rate of diffusion of liquids is higher than that of solids as liquids have higher inter-particle space than solids.

Hence, the correct option is the option (B).

Note: For gases, the rate of diffusion is inversely proportional to the square root of its molar mass. This is called Graham’s law of diffusion.
The rate of diffusion is higher in gases from that of liquids due to very less intermolecular forces of attraction between the gas molecules.