Chemical and Ionic Equilibrium 1 Question 48
50. $\mathrm{N}{2} \mathrm{O}{4}$ is $25 %$ dissociated at $37^{\circ} \mathrm{C}$ and one atmosphere pressure. Calculate (i) $K_{p}$ and (ii) the percentage dissociation at $0.1 \mathrm{~atm}$ and $37^{\circ} \mathrm{C}$.
$(1988,4 \mathrm{M})$
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Solution:
$$ \begin{aligned} & \mathrm{N}{2} \mathrm{O}{4} \rightleftharpoons 2 \mathrm{NO}{2} \quad \text { Total } \ & p{i}: \quad \begin{array}{cc} 1-\alpha & 2 \alpha \ \frac{1-\alpha}{1+\alpha} p & \frac{2 \alpha}{1+\alpha} p \end{array} \ & K_{p}=\frac{4 \alpha^{2}}{1-\alpha^{2}} p=\frac{4(0.25)^{2}}{1-(0.25)^{2}}=0.26 \mathrm{~atm} \end{aligned} $$
When $p=0.10 \mathrm{~atm}$
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