States of Matter - Result Question 66
66. To an evacuated vessel with movable piston under external pressure of $1 \hspace {1mm} atm, 0.1$ mole of $He$ and 1.0 mole of an unknown compound (vapour pressure $0.68 \hspace {1mm} atm$ at $0^{\circ} C$ ) are introduced. Considering the ideal gas behaviour, the total volume (in litre) of the gases at $0^{\circ} C$ is close to
(2011)
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Answer:
Correct Answer: 66. (7 L)
Solution:
Since, the external pressure is $1.0 \hspace {1mm} atm$, the gas pressure is also $1.0 \hspace {1mm} atm$ as piston is movable. Out of this $1.0 \hspace {1mm} atm$ partial pressure due to unknown compound is $0.68 \hspace {1mm} atm$.
Therefore, partial pressure of $He$
$ \begin{aligned} & =1.00-0.68=0.32 \hspace {1mm} atm . \\ \Rightarrow \quad \text { Volume } & =\frac{n(He) R T}{p(He)}=\frac{0.1 \times 0.082 \times 273}{0.32}=7 L \end{aligned} $
$\Rightarrow$ Volume of container $=$ Volume of He.
BETA
