Question

Rate of diffusion of gas A is 1/4 than that of gas B. If molar mass of has A is 36 g then the molar mass of gas B is:

• A. 2.25 g/mol
• B. 4.25 g/mol
• C. 3.16 g/mol
• D. 4.56 g/mol

Answer 1

The correct option is A 2.25 g/mol

$r_A=$ rate of diffusion of gas A = x/4

$r_B=$ rate of effusion of gas B = x

We know, $\frac{r_A}{r_B}=\sqrt{\frac{M_B}{M_A}}$

$\frac{x/4}{x}=\sqrt{\frac{M_B}{36}}$

$M_B=2.25$ g/mol