Question

$4g{H}_2$ and $127g{I}_2$ are mixed and heated lit closed vessels until equilibrium is reached. If the equilibrium concentration of $HI$ is $0.05M$ total number of moles present at equilibrium is:

• A. $3.25$
• B. $1.75$
• C. $2.25$
• D. $2.5$

Answer 1

The correct option is D $2.5$

Given $H_2=4g$ & $I_2=127g$

$\Rightarrow H_2=2$ mole & $I_2=0.5$ mole

$[HI{]}_{eqm}=0.05M$ $\therefore$ Moles of $HI=0.05$ mole

$H_2+I_2\rightleftharpoons 2HI$

$2$ $0.5$ $0$ Initial

$2-\frac{0.05}{2}$ $0.5-\frac{0.05}{2}$ $0.05$ Eqm

$\therefore$ Total moles at eqm,

$=(2-\frac{0.05}{2})+(0.5-\frac{0.05}{2})+0.05$

$=2.5$