Chemistry - Chemical Equilibrium Question with Solution | TestHub

$2HI\rightleftharpoons H_2+I_2$

$C(1-\alpha )$ $C\alpha /2$ $C\alpha /2$

$K_c=\frac{[H_2][I_2]}{[HI{]}^2}=\frac{\left(\frac{C\alpha }{2}\right)\left(\frac{C\alpha }{2}\right)}{[C(1-\alpha ){]}^2}=\frac{\frac{C^2{\alpha }^2}{4}}{C^2(1-\alpha {)}^2}=\frac{{\alpha }^2}{4(1-\alpha {)}^2}$

$K_c=\frac{(0.5{)}^2}{4(1-0.5{)}^2}=\frac{0.25}{4(0.5{)}^2}=\frac{0.25}{4(0.25)}=\frac{0.25}{1}=0.25$