Chemical and Ionic Equilibrium - Result Question 34
####34. When $NaNO _3$ is heated in a closed vessel, oxygen is liberated and $NaNO _2$ is left behind. At equilibrium,
(1986, 1M)
(a) addition of $NaNO _2$ favours reverse reaction
(b) addition of $NaNO _3$ favours forward reaction
(c) increasing temperature favours forward reaction
(d) increasing pressure favours reverse reaction
35 For the gas phase reaction,
$$ C _2 H _4+H _2 \rightleftharpoons C _2 H _6 \quad(\Delta H=-32.7 kcal) $$
carried out in a vessel, the equilibrium concentration of $C _2 H _4$ can be increased by
$(1984,1 M)$
(a) increasing the temperature
(b) decreasing the pressure
(c) removing some $H _2$
(d) adding some $C _2 H _6$
Fill in the Blanks
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Solution:
- $NaNO _3(s) \rightleftharpoons NaNO _2(s)+\frac{1}{2} O _2(g), \Delta H>0$
$NaNO _3$ and $NaNO _2$ are in solid state, changing their amount has no effect on equilibrium. Increasing temperature will favour forward reaction due to endothermic nature of reaction. Also, increasing pressure will favour backward reaction in which some $O _2(g)$ will combine with $NaNO _2(s)$ forming $NaNO _3$.
