Question

For the reaction $N_2{O}_4\left(g\right)\rightleftharpoons 2N{O}_2\left(g\right)$, if percentage dissociation of $N_2{O}_4$ are $20\%,45\%,65\%$ and $80\%$, then the sequence of observed vapour densities will be:

• A. $d_{20}>d_{45}>d_{65}>d_{80}$
• B. $d_{80}>d_{65}>d_{45}>d_{20}$
• C. $d_{20}=d_{45}=d_{65}=d_{80}$
• D. $(d_{20}=d_{45})>(d_{65}=d_{80})$

Answer 1

The correct option is A $d_{20}>d_{45}>d_{65}>d_{80}$

$(VD{)}_{mix}=\frac{M_{mix}}{2}=\frac{M}{2(1+\alpha )}$
So, as $\alpha$ increases $(VD{)}_{mix}$ decreases.

Hence, option $A$ is correct.