Consider following reactions is equilibrium with equilibrium concentration 0.01M of every species `:`
`I:PCl_(5) hArr PCl_(3)+Cl_(2)`
`II: H_(2)+I_(2)hArr 2HI`
`III: N_(2)+3H_(2)hArr 2NH_(3)`
Extent of the reactions taking place is `:`

Options

A. `I=II=III`
B. `Il lt II lt III`
C. `III lt II lt I`
D. `II lt I lt III`

Answer

B

Explanation

Here, molar concentration of each species at equilibrium`=0.01M`
`I. PCl_(5)hArr PCl_(3)+Cl_(2)`
`K=([PCl_(3)][Cl_(2)])/([PCl_(5)])=(0.01xx0.01)/(0.01)`
`=0.01 =10^(-2)`
`II. H_(2)+I_(2)hArr 2HI`
`K=([HI]^(2))/([H_(2)][I_(2)])=((0.01)^(2))/((0.01)xx(0.01))=1`
`III. N_(2)+3H_(2)hArr 2NH_(3)`
`K=([NH_(3)]^(2))/([N_(2)][H_(2)]^(3))=((0.01)^(2))/((0.01)xx(0.01)^(3))`
`=(1)/((0.01)^(2))=10^(4)`
More K, more is the extent of reaction
`:. ` Order of extent of reaction
`IltIIltIII`