Question

4.5 moles each of hydrogen and iodine heated in a sealed ten litre vessel. At equilibrium, 3 moles of HI were found. The equilibrium constant for $H_{2\left(g\right)}+I_{2\left(g\right)}$ $\rightleftharpoons$ ${2HI}_{\left(g\right)}$ is:

• A. 1
• B. 10
• C. 5
• D. 0.33

Answer 1

The correct option is A 1

$H_2+I_2\rightleftharpoons 2HI$

$Initialconc.4.54.50$

$4.5-x4.5-x2x$

From given data,

$2x=3\left(MolesofHI\right)$

$x=\frac{3}{2}=1.5$

$K=\frac{{\left[HI\right]}^2}{\left[I_2\right]\left[H_2\right]}=\frac{{\left(2x\right)}^2}{(4.5-x)(4.5-x)}$
substituting values of x we get,

$=\frac{3^2}{3\times 3}=1$

Hence, the option $\left(A\right)$ is the correct answer.