# For the equilibrium, If the value of Kc is 3, the percentage by mass of iso-butanein the equilibriummixture would be:- a) 75% b) 90% c) 30% d) 60% Kindly answer sir/mam.

1. Kc for the above reaction is represented as :

2. So concentration of isobutane is thrice of butane in a 100% solution of the two.
Thus isobutane = 75%
butane = 25%