Question

If the ratio of the rates of diffusion of two gases $A$ and $B$ is $4 : 1$, the ratio of their densities in the same order is

• A. $16 : 1$
• B. $1 : 4$
• C. $4 : 1$
• D. $1 : 16$

Answer 1

Answer: (D)

$1 : 16$

Answer 2

Rate of diffusion,
$r \propto \frac{1}{\sqrt{\text { density }, d}}$
$\Rightarrow \frac{r_{A}}{r_{B}}=\sqrt{\frac{d_{B}}{d_{A}}}$
or $\frac{4}{1}=\sqrt{\frac{d_{B}}{d_{A}}}$
$\frac{d_{A}}{d_{B}}=1: 16$