Relative volatility varies with the concentration of component for an ideal solution. The relative volatity of a binary mixture may be defined as the ratio of vapor pressure of component 'A' to that of component 'B', when

ANS:D - Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law.

The relative volatility of a binary mixture may be defined as the ratio of the vapor pressure of component 'A' to that of component 'B' when: Liquid phase obeys Raoult's law and vapor phase obeys Dalton's law. In an ideal solution, where Raoult's law holds for the liquid phase and Dalton's law holds for the vapor phase, the relative volatility is defined as the ratio of the vapor pressures of the two components at a given temperature. So, the correct option is: Vapor phase obeys Dalton's law and liquid phase obeys Raoult's law.