States of Matter - Result Question 66
####66. To an evacuated vessel with movable piston under external pressure of $1 atm, 0.1$ mole of $He$ and 1.0 mole of an unknown compound (vapour pressure $0.68 atm$ 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)
Subjective Questions
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Answer:
Correct Answer: 66. $(7 L)$
Solution:
- Since, the external pressure is $1.0 atm$, the gas pressure is also $1.0 atm$ as piston is movable. Out of this $1.0 atm$ partial pressure due to unknown compound is $0.68 atm$.
Therefore, partial pressure of $He$
$$ \begin{aligned} & =1.00-0.68=0.32 atm . \ \Rightarrow \quad \text { Volume } & =\frac{n(He) R T}{p(He)}=\frac{0.1 \times 0.082 \times 273}{0.32}=7 L \end{aligned} $$
$\Rightarrow$ Volume of container $=$ Volume of He.
