Question

If the equilibrium constant of the reaction,
$2HI\left(g\right)\rightleftharpoons H_2\left(g\right)+I_2\left(g\right)$ is $0.25$, the equilibrium constant of $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$, under similar conditions, will be:

• A. $4.0$
• B. $3.0$
• C. $2.0$
• D. $1.0$

Answer 1

The correct option is A $4.0$

If the equilibrium constant of the reaction,
$2HI\left(g\right)\rightleftharpoons H_2\left(g\right)+I_2\left(g\right)$ is $0.25$, the equilibrium constant of $H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$, under similar conditions, will be
$\frac{1}{0.25}=4$
Note: When an equation is reversed, the equilibrium constant is obtained by taking reciprocal of the equilibrium constant of original reaction.
$2HI\left(g\right)\rightleftharpoons H_2\left(g\right)+I_2\left(g\right)$ $K_1$
$H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$ $K_2$
$K_2=\frac{1}{K_1}$