Question

Equal weights of ethane & hydrogen are mixed in an empty container at ${25}^{\circ }C$. The fraction of the total pressure exerted by hydrogen is:

• A. $1:2$
• B. $1:1$
• C. $1:16$
• D. $15:16$

Answer 1

Answer: (D)

$15:16$

Let $x$ grams of each gas is mixed.

A Mole of ethane is $x/30$.
A mole of hydrogen is $x/2$.
Mole fraction of hydrogen is $\frac{\frac{x}{2}}{\frac{x}{2}+\frac{x}{30}}=\frac{15}{16}$

Partial pressure of hydrogen/total pressure = mole fraction of hydrogen $=15:16$

So, the correct option is $D$