Question

if the rate of diffusion of a gas is r and its density d, then under similar conditions of pressure and temperature _______.

• A. $r\propto d$
• B. $r\propto \sqrt{d}$
• C. $r\propto \frac{1}{\sqrt{d}}$
• D. $r\propto \frac{1}{d}$

Answer 1

The correct option is C

$r\propto \frac{1}{\sqrt{d}}$

Explanation for the correct answer:

Graham's law of diffusion of gases: It states that the rate of diffusion if different gases are inversely proportional to the square root of their densities at constant temperature and pressure.

Mathematically, Graham's law is $r=\frac{1}{\sqrt{d}}$

Explanation for the incorrect answer:

(a) Rate of diffusion of gas is directly proportional to the density of gas.

(b) Rate of diffusion is directly related to the square root of the density of gas.

(d) Rate of diffusion is inversely related to the density of gas.

Hence, option (c) is the correct answer.