(i) Derive a general expression for the equilibrium constant K_(p), and K_(c) for the reaction.(ii) Write the K_(p) and K_(C) for NH_(3) formation reaction.

(i) Derive a general expression for the equilibrium constant K_(p), an

1.	(i) Derive a general expression for the equilibrium constant K_(p), and K_(c) for the reaction.(ii) Write the K_(p) and K_(C) for NH_(3) formation reaction.
Answer» Solution : Consider a general REACTION in which all reactants and products are ideal gases. `xA+yBleftrightarrowIC+mD` The equilibrium constant `K_(C)`is `K_(C)=([C]’[D])/( [A]^(x)[B]^(y))`...(1) `K_(p)=(pcxxp_(D)^(m))/(p_(A)^(x)xxp_(B)^(m))`......(2) The ideal gas equation is PV = NRT or `Pprop(n)/(V)RT` Since, Active mass = molar concentration =`(n)/(V)` P=`Active massxxRT` Based on the above expression, the partial pressure of the reactants and products can be expressed as, By comparing equation (1) and (4), we get `K_(p)=K_(C)(RT)^((Deltang))` ...(5) where `Deltan_(g)` is the difference between the sum of NUMBER of moles of products and the sum of number of moles of reactants in the gas phase. 1. If `Deltan_(g)=0` ,`K_(p)=K_(C)(RT)^(0)`, `K_(p)=K_(C)` Example: `H_(2)(g)+L(g)leftrightarrow2HI(g)` 2. When `Deltan_(g)=+ve` `K_(P)=K_(C)` Example: `2NH_(3)(g)leftrightarrowN_(2)(g)+3H_(2)(g)` 3. When `Deltan_(g)=-ve` `K_(R)=K_(C)(RT)^(-ve)` Example : `2SO_(2)(g)+O_(2)(g)leftrightarrow2SO_(3)(g)` (ii) `N_(2)+3H_(2)leftrightarrow2NH_(2)` `K_(p)=(P^(2)NH_(3))/(P_(N_(2))P^(3)H_(2))``K_(C)=([NH_(3)]^(2))/([N_(2)][H_(2)]^(3))`