when we add a non-volatile solute to the solution it's boiling point increases , thus when we add the same - Chemistry - Solutions

Question

when we add a non-volatile solute to the solution it's boiling
point increases , thus when we add the same non-volatile solute to
the solution why does it's melting point decease instead of
increasing ? Pls explain in terms of vapour pressure

Vartika Jain · Accepted Answer

Dear Student,

When non-volatile solute is added to solvent, it decreases the
vapour pressure of the solvent Now, at freezing point, vapour
pressure of solid and liquid must be same, or else the system will
not be in equilibrium Lowering of the vapour pressure leads to
lowering of the temperature at which the vapour pressure of liquid
and frozen forms of the solution will be equal As a result,
depression in freezing point of solution is observed
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when we add a non-volatile solute to the solution it's boiling point increases , thus when we add the same non-volatile solute to the solution why does it's melting point decease instead of increasing ? Pls explain in terms of vapour pressure.