Question

Which one of the following oxides is most stable? The equilibrium constants are given at the same temperature:

• A. $2N_2{O}_5\left(g\right)\rightleftharpoons {2N}_2\left(g\right)+5O_2\left(g\right);K=1.2\times {10}^{34}$
• B. $2N_{2}O\left(g\right)\rightleftharpoons 2N_2\left(g\right)+O_2\left(g\right);K=3.5\times {10}^{35}$
• C. $2NO\left(g\right)\rightleftharpoons N_2\left(g\right)+O_2\left(g\right);K=2.2\times {10}^{30}$
• D. $2N{O}_2\left(g\right)\rightleftharpoons N_2\left(g\right)+2O_2\left(g\right);K=6.71\times {10}^{16}$

Answer 1

Answer: (D)

$2N{O}_2\left(g\right)\rightleftharpoons N_2\left(g\right)+2O_2\left(g\right);K=6.71\times {10}^{16}$

The following oxides is most stable as it has lowest value of the equilibrium constant.
$2N{O}_2\left(g\right)\rightleftharpoons N_2\left(g\right)+2O_2\left(g\right);K=6.71\times {10}^{16}$
Low value of the equilibrium constant means that the extent of the forward reaction is small. So the decomposition of nitrogen dioxide occurs to small extent. So the oxide has high stability.