I do not know how to take the equlibria constant for a heterogeneous equilibrium ...please help me with an example and tell me what to take and what not to.

Asked by reeya tanwar | 17th Nov, 2015, 11:37: PM

Expert Answer:

For heterogeneous reactions, the concentration terms for pure solids and pure liquids are not included in the expression for equilibrium constant. The concentration of pure solids and liquids remain constant, and these terms are merged into the equilibrium constant or by convention their concentrations are taken as unity, i.e., [solid] = 1, [liquid] = 1.


H2O(g) + C(s) ⇌ H2(g) + CO(g)


So, equilibrium constant can be given as,

begin mathsize 12px style straight K subscript straight c space equals space fraction numerator left square bracket straight H subscript 2 right square bracket space left square bracket CO right square bracket over denominator left square bracket straight H subscript 2 straight O right square bracket end fraction end style ; [C(s) = 1]

Answered by Arvind Diwale | 19th Nov, 2015, 09:58: AM