Which of the following statements about Graham's law are correct?

AThe rate of diffusion of a gas is inversely proportional to the square root of its density at constant $T$ and $P$
BUnder identical conditions $H X_{2}$ diffuses four times as fast as $O X_{2}$
CThe rate of diffusion of a gas is directly proportional to its pressure at constant temperature
DGases with equal vapour densities diffuse at equal rates under identical conditions

Answer: A, B, C, D

Graham's law:

r \propto \frac{P}{M}

, and

d \propto M

at fixed

T

and

P

, so (A) and (C) hold.

\frac{r _{H X_{2}}}{r _{O X_{2}}} = 32/2 = 4

(B). Equal vapour density means equal molar mass, so equal rates (D). All four are correct.