Define equilibrium constant. Write the equilibrium constant expression for the reaction of
`H_(2)(g)+I_(2)(g)hArr2HI(g)`
and its reverse reaction. How are the two equilibrium constants related?

Explanation

Equilibrium constant: The equilibrium constant, `K_(c)` may be defined as the ratio of product of the equilibrium concentrations of the products to that of the reactants with the each concentration term raised to the power equal to the stoichiometric coefficient of the substance in the balanced chemical equation.
For `H_(2)(g)+I_(2)(g)hArr 2HI(g)`
`K_(C_(1))=([HI]^(2))/([H_(2)][I_(2)])`
For the reverse reaction
`2HI(g)hArrH_(2)(g)+I_(2)(g)` ltbr. `K_(C_(2))=([H_(2)[I_(2)])/([HI]^(2)), K_(C_(1))=1/(K_(C_(2)))`