Question

A 600 $ml$ vessel containing oxygen at 800 $mm$ and a 400 $ml$ vessel containing nitrogen at 600 $mm$ at the same temperature are joined to each other. The final pressure of the mixture is:

• A. 1400 $mm$
• B. 720 $mm$
• C. 1000 $mm$
• D. 700 $mm$

Answer 1

Answer: (B)

For an ideal gas equation;
$PV=nRT$

$\therefore$ For $O_2$ , no. of moles = $\frac{PV}{RT}$ = $\frac{0.6\times 800}{RT}=\frac{480}{RT}$

For $N_2$, no. of moles = $\frac{0.4\times 600}{RT}=\frac{240}{RT}$

Total no. of moles = $\frac{480}{RT}+\frac{240}{RT}=\frac{720}{RT}$ = n

$\therefore$ Pressure of final mixture = $\frac{nRT}{Totalvolume}=\frac{720}{RT}\times \frac{RT}{1}$ = 720 $mm$