how to solve this problem

Question

A solution is made by dissolving  of nonelectrolyte solute in  of benzene. Calculate the freezing point,  and boiling point,  of the solution. Constants can be found in the .

Answer 1

A non electrolyte when dissolved in a solvent does not produce more than 1 particle, i.e. it doesn't ionize or dissociate.

In the present problem, we cannot calculate the freezing point, or boiling point because we don't know how much of the non electrolyte was added and we don't know how much benzene there is. So, the question is incomplete.

Answer 2

This is known as a problem in 'colligative properties'. The phenomena are known as freezing point depression and boiling point elevation, and they are described by simple equations relating the concentration of solute (normally as molality) to the depression or elevation, via material specific constants. You should be able to find these in your text or online with little difficulty.