Chemical and Ionic Equilibrium 1 Question 23
24. One mole of $\mathrm{N}{2} \mathrm{O}{4}(\mathrm{~g})$ at $300 \mathrm{~K}$ is kept in a closed container under one atmosphere. It is heated to $600 \mathrm{~K}$ when $20 %$ by mass of $\mathrm{N}{2} \mathrm{O}{4}(g)$ decomposes to $\mathrm{NO}_{2}(g)$. The resultant pressure is
(1996, 1M)
(a) $1.2 \mathrm{~atm}$
(b) $2.4 \mathrm{~atm}$
(c) $2.0 \mathrm{~atm}$
(d) $1.0 \mathrm{~atm}$
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Solution:
$$ \mathrm{N}{2} \mathrm{O}{4} \rightleftharpoons 2 \mathrm{NO}_{2} $$
$$ \begin{array}{lccl} \text { At } 300 \mathrm{~K}: & 1.0 \mathrm{~atm} & 0 & \ \text { At } 600 \mathrm{~K}: & 2.0-0.40 & 0.80 \quad \text { Total pressure }=2.40 \mathrm{~atm} \end{array} $$
