Question

A cylinder contains 0.3 mole $N_2$, 0.1 mole $O_2$ and 0.1 mole $He$. If the total pressure of gas mixture is 1 atmosphere, the partial pressure of $O_2$ in $mm$ of $Hg$ is:

• A. 152
• B. 304
• C. 380
• D. 760

Answer 1

The correct option is A 152

Moles of $N_2$ = 0.3

Moles of $O_2$ = 0.1

Moles of $He$ = 0.1

Mole fraction of $O_2$ = ${\Lambda }_{O_2}=\frac{n_{O_2}}{n_{N_2}+n_{O_2}+n_{He}}=\frac{0.1}{0.3+0.1+0.1}=0.20$

Total pressure = 1 atm

1 atm = 760 mm of $Hg$

Partial Pressure of $O_2={\Lambda }_{O_2}\times$ Total pressure = 0.02 $\times$ 760 mm of Hg = 152 mm of $Hg$