Question

20% of $N_2{O}_4$ molecule are dissociated in a sample of gas at 27 degree C and 760 torr mixture has the density at the equilibrium

Answer 1

Given that,

Degree of dissociation $\left(\alpha \right)=20$

Number of moles formed $n=2$

Substituting above values in Vant Hoff factor expression

$0.2=\left(\frac{i-1}{2-1}\right)$

$i=1.2$

We know that,

Normal molar mass of $N_2{O}_4=92$

Normal molar mass of $N{O}_2=46$

So abnormal molar mass of mass of each would be

$N_2{O}_4=\frac{92}{1.2}=76.67$

$N{O}_2=\frac{46}{1.2}=38.33$

According to ideal gas equation,

$d_{N_2{O}_4\text{A}}A=\frac{PM}{RT}=\frac{1\ast 76.67}{0.0821\ast 300}=3.11g/c{m}^3$

Similar,

$d_{N{O}_2}=\frac{1\times 38.33}{0.0821\times 300}A=1.56g/c{m}^3$

Total density of equilibrium mixture$=3.11+1.56=4.67g/c{m}^3$