Raoult’s law posits a direct proportionality between the partial vapor pressure of any volatile component within a solution and its corresponding mole fraction. This relationship is expressed mathematically as: \[P_A = X_A \cdot P_A^\circ\]In this equation, \( P_A \) denotes the partial vapor pressure of component A, \( X_A \) represents its mole fraction, and \( P_A^\circ \) signifies the vapor pressure of pure component A.
The vapor pressure of an aqueous glucose solution is diminished compared to that of pure water due to glucose being a non-volatile solute. An increase in glucose molecules within the solution leads to a reduction in the number of water molecules at the surface, consequently lowering the vapor pressure. This phenomenon illustrates a colligative property, where the depression in vapor pressure is directly proportional to the quantity of solute present.