Question

The value of $K_c$ for the reaction $2HI\left(g\right)\rightleftharpoons H_2\left(g\right)+I_2\left(g\right)$ is $1\times {10}^{-4}$. At a given time, the composition of reaction mixture is $\left[HI\right]=2\times {10}^{-5}$ mol and $\left[I_2\right]=1\times {10}^{-5}$ mol. The direction in which the reaction will proceed is (For forward direction write 0 and for reverse direction write 1)

Answer 1

At a given time the reaction quotient Q for the reaction will be given by the expression:

$Q=\frac{\left[H_2\right]\left[I_2\right]}{\left[HI\right]}=\frac{1\times {10}^{-5}\times 1\times {10}^{-5}}{(2\times {10}^{-5}{)}^2}=\frac{1}{4}$

$=0.25=2.5\times {10}^{-1}$

As the value of the reaction quotient is greater than the value of $K_c$ i.e. $1\times {10}^{-4}$ the reaction will proceed in the reverse direction.