Which of the following liquid pairs shows a positive deviation from Raoult’s law? — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

Consider a solution composed of two components A and B. If when the components have a lower force of attraction between A and B and A and A or B and B have greater forces of attraction, then the solution exhibits a positive deviation in Raoult's law. The benzene reduces the H-bonding strength between the methanol molecules. Therefore, the mixture has a greater rate of evaporation and has a lower boiling point. It exhibits a positive deviation from Raoult's law. Therefore, the benzene –methanol mixture has weaker intermolecular forces than the pure liquids. Thus, (b) is the correct option.