Question

If the density of a gas at ${27}^0$ $C$ and 1 atmospheric pressure is $1.8$ ($g/L$) ,its molecular mass is :

• A. 44.33
• B. 42.25
• C. 44.38
• D. 43.44

Answer 1

The correct option is A 44.33

Density $d=\frac{molarmass}{volume}=\frac{M}{V}\Rightarrow V=\frac{M}{d}$

From the gas law $PV=nRT$

$\Rightarrow V=\frac{nRT}{P}\Rightarrow M=\frac{dRT}{P}$

Substituting the values in the formula:

$M=(1.8\times 0.082\times 300)/1=44.33g$