An ideal liquid solution of two volatile components is in equilibrium with its vapour. The vapour pressure of pure liquid component A is 400 mm Hg. If the mole fraction of component A is 0.25 in the liquid phase and 0.2 in the vapour phase, the total pressure of the gaseous mixture is ________ mm Hg.

Step-by-step solution

According to Raoult's law, the partial pressure of component A is: P_A = P_A^o x_A P_A = 400 0.25 = 100 mm Hg According to Dalton's law of partial pressures, the partial pressure of component A in the vapour phase is related to the total pressure P_T by: P_A = y_A P_T 100 = 0.2 P_T P_T = 100 0.2 = 500 mm Hg Answer: 500