Question

Equal weights of methane and hydrogen are mixed in an empty container at ${25}^{o}C$. The fraction of the total pressure exerted by hydrogen is:

• A. $\frac{1}{2}$
• B. $\frac{8}{9}$
• C. $\frac{1}{9}$
• D. $\frac{16}{17}$

Answer 1

Answer: (B)

$\frac{8}{9}$

Molar ratio of $C{H}_4$ : $H_2$ = 16 : 2 = 8 : 1 (Mixed in equal quantities)

Pressure is directly proportional to a number of moles.
Methane is 8/9 of total no. of moles.
So,
Fraction of pressure by $C{H}_4$ = 8/9 .

Hence $\frac{8}{9}$ is the answer.