Question

The total volume of a mixture of $2gm$ of helium and $7gm$ of nitrogen under $STP$ conditions is:

• A. 22.4 $L$
• B. 11.2 $L$
• C. 16.8 $L$
• D. 5.6 $L$

Answer 1

The correct option is C 16.8 $L$

$2gms$ helium corresponds to $0.5mole$.

Mass of nitrogen atom $=14gm$

Molecular mass of nitrogen $\left(N_2\right)$ $=28gm$

$⟹7gm$ nitrogen corresponds to $0.25mole$.

Thus, total $0.75mole$ of helium and nitrogen are present.

At $STP$, they will occupy $0.75\times 22.4L=16.8L$.