Question

'x' g of molecular oxygen (O2) is mixed with 200 g of neon (Ne). The total pressure of the non-reactive mixture of O2 and Ne in the cylinder is 25 bar. The partial pressure of Ne is 20 bar at the same temperature and volume. The value of 'x' is ___.
[Given : Molar mass of O2 = 32 g mol-1 and Molar mass of Ne = 20 g mol-1]

Answer 1

$P_{O_2}=25−20=5$ bar
$P_{O_2}=X_{O_2}×P_{Total}$
$\frac {5}{25}=\frac {n_{O2}}{n_{O_2}+n_{Ne}}$

$\frac 15=\frac {\frac {x}{32}}{\frac {x}{32}+\frac {200}{20}}$

$⇒\frac {x}{32}+10=\frac {5x}{32}$

$⇒\frac x8=10$
$⇒x=80$ gm

So, the answer is $80$.