Question

At certain temperature 2HI gives H2+I2 only 50% HI is dissociated at equilibrium .the equilibrium constant is

Answer 1

Answer is 0.0625 hope that will help you    

Answer 2

Answer: The equilibrium constant is 1.

Explanation:

               $2HI\rightleftharpoons H_2+I_2$

initial         c         0   0

at eq'm     c-c$\alpha$    $c\alpha$  $c\alpha$

Expression for equilibrium constant is written as:

$K_c=\frac{[H_2][I_2]}{[HI]^2}=\frac{c\alpha\times c\alpha}{c^2(1-\alpha)^2}=\frac{\alpha^2}{(1-\alpha)^2}$

On putting value of $\alpha= 0.5$, we get:

$K_c=1$

Hence,The equilibrium constant is 1.