Question

Which of the following scenarios depict an example of colligative properties at play: (A) Pure water freezes at a higher temperature than pure methanol. (B) A 0.5 m NaOH solution freezes at a lower temperature than pure water. (C) A 0.5 m NaBr solution has a higher vapor pressure than a 0.5 m BaCl2 solution.

Answer 1

Answer:

(B)

Explanation:

The colligative properties of any given solution are properties that are dependent on the concentration of the molecules or ions of the solute in the solution, and not on the type or identity of that solute. Examples of colligative properties:

1. Lowering of vapour pressure  

2. Elevation of boiling point,

3. Depression of freezing point and

4. Osmotic pressure

(A) is not a colligative property because the scenario talks about the freezing point of a pure solvent and not a solution.

(C) is not a colligative property because the solutions being compared are completely different (the solutes are different).  

(B) is a colligative property because it talks about the freezing point of a solution