Question

7. Which of the following will have the highest boiling point? Justify your answer. A. 0.10 m sodium sulfate B. 0.20 m potassium fluoride C. 0.20 m ethanol D. 0.10 magnesium nitrate

Answer 1

Answer is B). 0.20 m potassium fluoride.

On adding non volatile solute, boiling point of solution increases. This elevation in boiling point depends on number of moles of solute since potassium fluoride dissociate to give two ions (potassium and fluoride) hence it's moles is 2×0.2 = 0.4. since it contain most moles it's boiling point is high.