Question

Equal weights of methane and hydrogen are mixed in an empty container at $25^\circ$ C The fraction of the total pressure exerted by hydrogen is

• A. $\frac{1}{2}$
• B. $\frac{8}{9}$
• C. $\frac{18}{17}$
• D. $\frac{16}{17}$

Answer 1

The Correct Option is B

The correct option is(B): \(\frac{8}{9}\).

Let .v grams of each hydrogen and methane are mixed 
\(\, \, \, \, \, \, \, \, \, \, \, \, \, \, \, Moles\, of\, H_2=\frac{x}{2}\)
\(\, \, \, \, \, \, \, \, \, \, \, \, \, \, \, Moles\, of\, CH_4=\frac{x}{16}\)
\(\Rightarrow \, \, \, \, \, \, Mole fraction of H_2 =\frac{\frac{x}{2}}{\frac{x}{2}+\frac{x}{16}}=\frac{8}{9}\)
\(\Rightarrow \, \, \, \, \frac{Partial\, pressure\, of\, H_2}{Total\, pressure }=Mole\, fraction\, of\, H_2=\frac{8}{9}\)