Explain why on the addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while the addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.
Explain why on the addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while the addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.

Adding 1 mol of NaCl to 1 liter of water, a point of boiling water rises, while the addition of 1 mol of methyl alcohol to one liter of water reduces its boiling point because when added to a stable solute such as NaCl this occurs. Methyl alcohol does not change more than water, so it reduces the boiling point.