$\mathrm{K}_{\mathrm{C}}=\frac{\left[\mathrm{FeSCN}^{2+}\right]}{\left[\mathrm{Fe}^{3+}\right]\left[\mathrm{SCN}^{-}\right]}$
$2S{O_2} + {O_2}$ $\rightleftharpoons$ $2S{O_3} + Q$ $Cal$
${N_2}(g) + {O_2}(g) \rightleftharpoons 2NO(g)$
${N_2}{O_4}(g) \rightleftharpoons 2N{O_2}(g)$
${N_2}(g) + 3{H_2}(g) \rightleftharpoons 2N{H_3}(g)$