Question

Predict which of the following reaction will have appreciable concentration of reactants and products:
a) ${Cl}_2\left(g\right)\rightleftharpoons 2Cl\left(g\right);K_c=5\times {10}^{-39}$
b) ${Cl}_2\left(g\right)+2NO\left(g\right)\rightleftharpoons 2NOCl\left(g\right);K_c=3.7\times {10}^8$
c) ${Cl}_2\left(g\right)+2{NO}_2\left(g\right)\rightleftharpoons 2{NO}_{2}Cl\left(g\right);K_c=1.8$

Answer 1

When the value of the equilibrium constant is very small, the reactants predominate.
When the value of the equilibrium constant is very large, the products predominate.
When the value of the equilibrium constant is around 1, appreciable quantities of both reactants and products are present.
(a) The reaction has appreciable concentration of reactants.
(b) The reaction has appreciable concentration of products.
(c) Appreciable quantities of both reactants and products are present.