Which solute, when dissolved in 1 kg h2o, will give the solution with the highest boiling point? (a) 50 g ethylene glycol, hoch2ch2oh (b) 50 g hydroxyacetic acid, hoch2cooh (c) 50 g glycerol, hoch2chohch2oh (d) 50 g glyoxal, hcocho

D is the correct option.

Explanation:

In order to explain all the solutes from the excersise, the lowest molar mass will give the solution, the highest boiling point.

ΔT = Keb . m

Molality = mol of solute / 1kg of solute

Mol of solute = mass / molar mass

If the molar mass↓ it's small, mol of solute will be↑

Mol of solute ↑ ,  generates high molality

ΔT ↑ = Kf . m ↑

If the molality is high, the difference between the temperautes, will be high, so the boiling point from solution, will be higher.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.