Question

Vapour density of the equilibrium mixture of the reaction
$2{NH}_3\left(g\right)\rightleftharpoons N_2\left(g\right)+3H_2\left(g\right)$ is $6.0$
Percent dissociation of ammonia gas is:

• A. $13.88$
• B. $58.82$
• C. $41.66$
• D. None these

Answer 1

The correct option is C $41.66$

${2NH}_3\rightleftharpoons N_2\left(g\right)+3H_2\left(g\right)$

$t=0$ $a$ $0$ $0$ $V.D\Rightarrow \frac{M.W}{2}$ of mixture

$t=t_{eq}$ $a-x$ $x/2$ $3x/2$ ${M.W}_{mix}=12$

$\Rsh$ total weight

${M.W}_{mix}\Rightarrow \frac{n_1{a}_1+n_2{a}_2}{n_1+n_2}\Rightarrow \frac{(a-x)\times \left(17\right)+\left(x/2\right)\times \left(28\right)+\left(3x/2\right)\times \left(2\right)}{a+x}=12$

total moles $\hookleftarrow$

$\Rightarrow \frac{17a}{a+x}=12\Rightarrow 17a=12a+12x$

$5a=12x$

$\alpha =\frac{x}{a}=\frac{5}{12}=41.667$%