# A mixture of one mole each of

Question:

A mixture of one mole each of $\mathrm{H}_{2}, \mathrm{He}$ and $\mathrm{O}_{2}$ each are enclosed in a cylinder of volume $V$ at temperature $T$. If the partial pressure of $\mathrm{H}_{2}$ is $2 \mathrm{~atm}$, the total pressure of the gases in the cylinder is :

1.  $6 \mathrm{~atm}$

2. $38 \mathrm{~atm}$

3. $14 \mathrm{~atm}$

4.  $22 \mathrm{~atm}$

Correct Option: 1

Solution:

$P_{\mathrm{gas}}=\frac{n_{\mathrm{gas}} R T}{V}$

As $n, T$ and $V$ constant so $P_{\mathrm{H}_{2}}=P_{\mathrm{O}_{2}}=P_{\mathrm{He}}=2 \mathrm{~atm}$

So, $P_{\text {Total }}=P_{\mathrm{H}_{2}}+P_{\mathrm{O}_{2}}+P_{\mathrm{He}}=6 \mathrm{~atm}$