States of Matter - Result Question 27
27. Equal weights of ethane and hydrogen are mixed in an empty container at $25^{\circ} C$. The fraction of the total pressure exerted by hydrogen is
$(1993,1 M)$
(a) $1: 2$
(b) $1: 1$
(c) $1: 16$
(d) $15: 16$
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Answer:
Correct Answer: 27. (d)
Solution:
Let $x \hspace {1mm} g$ of each gas is mixed.
$ \begin{aligned} \text { Mole of ethane } & =\dfrac{x}{30} \\ \text { Mole of hydrogen } & =\dfrac{x}{2} \end{aligned} $
Mole fraction of hydrogen $=\dfrac{\dfrac{x}{2}}{\dfrac{x}{2}+\dfrac{x}{30}}=\dfrac{15}{16}$
$ \Rightarrow \quad \dfrac{\text { Partial pressure of } H _2}{\text { Total pressure }}=\text { Mole fraction of hydrogen } $
$ \hspace{20mm} =15:16$
BETA
