Question

A closed vessel contains $8\, g$ of oxygen and $7\, g$ of $N _{2}$ Total pressure is 10 atm at a given temperature. If now oxygen is absorbed by introducing a suitable absorbent, the pressure of the remaining gas will be

• A. 2
• B. 10
• C. 4
• D. 5

Answer 1

Answer: (D)

$P_{\text {mix }}=P_{1}+P_{2}$
$P_{\text {mix }}=\frac{n_{1} R T}{V}+\frac{n_{2} R T}{V}$
$10=\frac{8 RT }{32 V }+\frac{7 RT }{28 V } $
$\Rightarrow 10=\frac{ RT }{2 V }$
$\Rightarrow \frac{ RT }{ V }=20$
If $O _{2}$ absorbed pressure by $N _{2}$
$P_{N_{2}}=\frac{7}{28} \frac{R T}{V}\left(\frac{2}{2}\right)$
$=\frac{10}{2}=5$ atm