Question

An aqueous solution of methanol in water has vapour pressure

• A. Equal to that of water
• B. Equal to that of methanol
• C. More than that of water
• D. Less than that of water

Answer 1

The correct option is C More than that of water

Methanol has low boiling point than water, hence its vapour pressure in pure form is higher than that of water.

Thus vapor pressure of the solution has higher pressure than water as shown in the figure below

Note that methanol water solution shows positive deviation from Roult’s Law.