The total pressure of a mixture of 6.4 grams of oxygen and 5.6 grams of nitrogen present in a 2 lit vessel is 1200mm. What is the partial pressure of nitrogen in mm?

The correct option is C i.e 600
No. of mole =$\frac{givenmass}{molarmass}$

$N_2=\frac{5.6}{28}\Rightarrow 0.2$

$O_2=\frac{6.4}{32}\Rightarrow 0.2$
Mole fraction of $N_2=\frac{0.2}{0.2+0.2}=\frac{1}{2}$

Partial Pressure of $N_2=$ mole fraction $\times totalpressureof{N}_2$

$\Rightarrow \frac{1}{2}\times 1200\Rightarrow 600mm$