4g H₂ and 127g I₂ are mixed & heated in 10 lit closed vessel until equilibrium is reached. If the equilibrium concentration of HI is 0.05 M, total number of moles present at equilbrium is

${\left[\mathrm{HI}\right]}_{\mathrm{eq}}=0.05 \mathrm{M}, \mathrm{V}=10 \mathrm{lit};$

${\left({\mathrm{n}}_{\mathrm{HI}}\right)}_{\mathrm{eq}}=0.5 ;$

1 mole of Hydrogen gives 2 moles of HI

'${\mathrm{X}}_1$' moles of Hydrogen gives 0.5 moles of HI.

Number of moles of Hydrogen reacted (${\mathrm{X}}_1$) = 0.25

Number of moles of Iodine reacted also will be 0.25

Stoichiometry
Initial moles	2	0.5		-
Mole at equilibrium	(2 - 0.25)	(0.5 - 0.25)		0.5

Total moles at equilibrium = 1.75+0.25+0.5

Total moles at equilibrium = 2.5