Question

When `NaNO_(3)` is heated in a closed vessel, oxygen is liberated and `NaNO_(2)` is left behind. At equilibrium,
A. increased temperature favors forward reaction
B. addition of `NaNO_2` favors reverse reaction
C. increased pressure favors forward reaction
D. adding of `NaNO_2` favors forward reaction

Answer 1

Correct Answer - A
`NaNO_(3)(s) hArr NaNO_(2)(s)+O_(2)(g)`
Decomposition is an enthermic reaction and a temperature increase favors an enthothermic reaction. In heterogeneous equilibrium such as this, the active masses of pure solids (being constant) do not appear in the reaction quotient expression `(Q)`. Thus, the addition of `NaNO_(3)(s)` or the addition of `NaNO_(2)(s)` does not change the value of Q. Hence, equilibrium is not disturbed. For this equilibrium, `Delta n_(g)` is `+ve`. Thus, increase in pressure in the number of moles of gas.