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Why is the vapous pressure of an aqueous...

Why is the vapous pressure of an aqueous solution of gulucose lower than that of water ?

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Glucose is a non-volatile solute. In pure water, the entire surface is occupied by volatile water molecules. On adding glucose, some of the volatile water molecules at the surface are replaced by non-volatile glucose moleules. Thus, evaporation of water from the surface gets reduced. Hence, vapour pressure is lowered.
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