Question

A gas $A$ diffuses at a rate which is twice that of another gas $B$. The ratio of molecular weight of $A$ to B is:

• A. 1
• B. 0.75
• C. 0.5
• D. 0.25

Answer 1

The correct option is D 0.25

$\frac{r_A}{r_B}=\sqrt{\frac{M_B}{M_A}}$

$2=\sqrt{\frac{M_B}{M_A}}$

$4=\frac{M_B}{M_A}$

$\frac{M_A}{M_B}=\frac{1}{4}=0.25$

Option D is correct.