• # question_answer In a chemical equilibrium, the rate constant of forward reaction is $75\times {{10}^{-4}}$and the equilibrium constant is 1.5. The rate constant backward reaction is A) $4.5\times {{10}^{4}}$                  B) $5\times {{10}^{-4}}$       C)      $2.5\times {{10}^{-4}}$    D)      $6\times {{10}^{4}}$

As $K=\frac{\text{Rate of forward reaction}}{\text{Rate of backward reaction}}=\frac{{{K}_{t}}}{{{K}_{b}}}$ $=\frac{7.5\times {{10}^{-4}}}{{{K}_{b}}}$ or         ${{K}_{b}}=\frac{7.5\times {{10}^{-4}}}{1.5}$ $=5\times {{10}^{-4}}$ Hence, the correct option is (a).