Question

Equal mass of $H_2$, $He$ and $C{H}_4$ are mixed in an empty container at 300 K when total pressure is 2.6 atm. The partial pressure of $H_2$ in the mixture is:

• A. 0.5 atm
• B. 1.6 atm
• C. 0.8 atm
• D. 1.22 atm

Answer 1

Answer: (B)

1.6 atm

We know that partial pressure of a gas is the product of the total pressure and the concentration or the mole fraction of a gas in the mixture.

Partial pressure = Total pressure $\times$ Mole fraction

Let the given mass of each gas be $x$.

We know that the atomic masses given below:

$H_2=2$

$He=4$

$C{H}_4=16$

So, we have the mole fraction of each gas which is given below:

$H_2=x/2$

$He=x/4$

$C{H}_4=x/16$

The total moles of the gas mixture $=0.8125x$

Now, to calculate the partial pressure of :$H_2$

Partial pressure = Total pressure × Mole fraction

$=\frac{\frac{x}{2}}{0.8125x}\times 2.6$

Partial pressure of $H_2$$=1.6$ atm

Hence, option $B$ is correct.