Question

Which has the lowest boiling point at 1 atm pressure?
(a) 0.1 M Kcl
(b) 0.1 M urea
(c) 0.1 M AlCl3​

Answer 1

Explanation:

Helium

The boiling point of a liquid at 1 atm is also known as the normal boiling point. It has been found that Helium has the lowest normal boiling point (−268.9 °C) because it has very weak intermolecular attractions.

Answer 2

The correct answer will be option b.

So, as the concentration of all the three compounds are the same ,the boiling point will be compared by using the van't hoff factor.

The van't hoff factor for the compunds will be as below

KCl : 2

urea : 1

AlCl3​ : 4

So the lowest  van't hoff factor  is of urea and therefore it will have the lowest boiling point.