Question

The density of a mixture of $O_2$ and $N_2$ gases at $1$ atm and $273$K is $0.0013$ gm/ml. If partial pressure of $O_2$ in the mixture is A then calculate value of $25$A.

Answer 1

Given density= $1.3gm/lit$ at STP

$1lit=1.3gm$

$\therefore 22.4lit=22.4\times 1.3=29.12gm$

$\therefore H.W=29.12gm$

Total weight of given mixture at $22.4lit$ STP is:

$\Rightarrow 28x\ne 32(1-x)$

$\Rightarrow 29.12=28x+32-32x$

$\Rightarrow x=0.72$

Number of moles of $N_2=0.72$ & $O_2=1-0.72=0.28$

$\therefore$ Partial pressure of $O_2$ at STP= $\frac{n_{O_2}}{n_{O_2}+n_{N_2}}\times P$

$=\frac{0.28}{(0.28+0.72)}\times 1$

$\Rightarrow P_{O_2}=0.28atm$ .