Why is the vapour pressure of an aqueous solution of glucose lower than that of pure water?
(N/A) The vapour pressure of a liquid is determined by the escaping tendency of its molecules from the surface. In pure water,the entire surface is occupied by water molecules. When a non-volatile solute like glucose is added,the glucose molecules occupy some space on the surface. This reduces the number of water molecules available at the surface to escape into the vapour phase. Consequently,the rate of evaporation decreases,leading to a lower vapour pressure for the solution compared to pure water. This phenomenon is a colligative property.
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