Question

Which of the following colligative properties is useful to determine the molar masses of proteins, polymers or colloids, with the greatest precision?

• A. Elevation in boiling point
• B. Depression in freezing point
• C. Osmotic pressure
• D. Relative lowering of vapour pressure

Hint:

Osmotic pressure is large enough to measure at low concentrations and at room temperature.

Answer 1

The Correct Option is C

Step 1: Problem
Macromolecules give very low molar concentrations.

Step 2: Compare
Changes in boiling point, freezing point and vapour pressure are very small at such concentrations, but $\pi$ is easily measurable and is done at a fixed room temperature.

Step 3: Answer
Osmotic pressure, option (C).

Final Answer:
Option (C). \[ \boxed{\text{Osmotic pressure}} \]