Answer to Question #154837 in Physical Chemistry for Mani

Question

Sketch the non-ideal vapour pressure-composition curve of element X and nitrous acid, HNO2 where the composition of azeotropic mixture is 40% X at 40ºC and the boiling point of X is higher than HNO2. Explain the vapour pressure of each composition and distillation process of above mixture using the curve

Answer 1

Solution.

If the solution has a composition indicated by point 1, then when the temperature drops to T1, the ratio of the amount of liquid phase to the gaseous phase will be the ratio of the lengths of the sections l2/l1. As the temperature decreases, the liquid phase is gradually enriched with component X. The concentration of the liquid phase changes along the lower curve t(HNO2) - H, and the vapor along the upper curve t(HNO2) - H. At a temperature below the H point, there will be an azeotropic mixture consisting of 40 % X and 60 % HNO2. If the solution has a composition indicated by point 2, then when the temperature is lowered to T2, the ratio of the amount of liquid phase to steam will be the ratio of the lengths of the sections m1/m2. As the temperature decreases, the liquid phase is gradually enriched with the HNO2 component. The concentration of the liquid phase varies along the lower curve t(X) - H, and the vapor along the upper curve t (X) - H. At a temperature below the H point, there will be an azeotropic mixture consisting of 40 % X and 60 % HNO2.

Answer:

If the solution has a composition indicated by point 1, then when the temperature drops to T1, the ratio of the amount of liquid phase to the gaseous phase will be the ratio of the lengths of the sections l2/l1. As the temperature decreases, the liquid phase is gradually enriched with component X. The concentration of the liquid phase changes along the lower curve t(HNO2) - H, and the vapor along the upper curve t(HNO2) - H. At a temperature below the H point, there will be an azeotropic mixture consisting of 40 % X and 60 % HNO2. If the solution has a composition indicated by point 2, then when the temperature is lowered to T2, the ratio of the amount of liquid phase to steam will be the ratio of the lengths of the sections m1/m2. As the temperature decreases, the liquid phase is gradually enriched with the HNO2 component. The concentration of the liquid phase varies along the lower curve t(X) - H, and the vapor along the upper curve t (X) - H. At a temperature below the H point, there will be an azeotropic mixture consisting of 40 % X and 60 % HNO2.