Question

At ${100}^{o}C$ the vapour density of nitrogen peroxide $\left(N_2{O}_4\right)$ is $26.8$. The percentage dissociation into $N{O}_2$ molecules is:

• A. $71.4\%$
• B. $61.57\%$
• C. $83.56\%$
• D. $67.39\%$

Answer 1

The correct option is A $71.4\%$

Percentage dissociation $=\frac{D-d}{d}\times 100$

$d=26.8$( Observed vapour density) and $D=\frac{Mwt}{2}=46$

Now, Percentage dissociation $=\frac{46-26.8}{26.8}\times 100=71.4\%$