Question

Assertion: When methanol is added to water, boiling point of water increases.
Reason: When a volatile solute is added to a volatile solvent, elevation in boiling point is observed.
A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation of Assertion.
C. Assertion is true but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: Elevation in boiling point of a solution is meaning that the boiling point of the solvent will be higher when a compound called solute is added to the solvent. It is nothing but the solution has higher boiling point than the pure solvent.

Complete answer:
- In the question it is given that methanol is added to the water and we have to find whether the boiling point of the water increases or decreases.
- Here methanol is the solute and water is the solvent.
- We know that methanol is a volatile solute.
- When methanol is added to the water the boiling point of the water decreases because easily volatile solutes make the solvent to evaporate at a lesser temperature when compared to normal solvent.
- That means water is going to evaporate at less temperature than the original boiling point of the water.
- Therefore both Assertion and Reason are wrong.

So, the correct option is D.

Note:
If we are going to add a non-volatile solute to the solvent then the solution shows an elevation in boiling point of the solution. Because the non-volatile solute makes the solvent to not evaporate at the original boiling point. Then the solution shows an elevation in the boiling point.