Question

For the reaction $N_2{O}_4\left(g\right)\rightleftharpoons 2N{O}_2\left(g\right)$, if percentage dissociation of $N_2{O}_4$ and $20$%, $45$%, $65$% 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 B $d_{80}>d_{65}>d_{45}>d_{20}$

$N_2{O}_4\rightleftharpoons 2N{O}_2$

$P_0$ $0$

$P_0(1-\alpha )P_0\left(2\alpha \right)$

observed vapour density $=P_0(1-\alpha )+P_0\left(2\alpha \right)$

$=P_0(1+\alpha )$

As $\alpha$ increases vapour density increases

$d_{80}>d_{65}>d_{45}>d_{20}$