Chemistry · Surface Chemistry

JEE Advanced 2021 — Paper 1 — Question 16

The correct statement(s) related to colloids is(are)

Option A:
The process of precipitating colloidal sol by an electrolyte is called peptization.
Option B:
Colloidal solution freezes at higher temperature than the true solution at the same concentration.
Correct
Option C:
Surfactants form micelle above critical micelle concentration (CMC). CMC depends on temperature.
Correct
Option D:
Micelles are macromolecular colloids.

Answer: B, C

Step-by-step solution

(A) Process of precipitating colloidal solution by using an electrolyte is called "COAGULATION" and not peptisation.

(B) Since, molar mass of sol is much higher than true solutions, so magnitude of any colligative properties is smaller than true solutions.

$\left(\Delta T_{f}\right)_{\text {sol }}<\left(\Delta T_{f}\right)_{\text {true solution }}$ So, freezing point of sols $>$ freezing point of true solution.

So, option (B) is correct. (C) Micells are formed greater than or equal to CMC and above KRAFT temperature.

So option (C) is also correct. (D) Micelles are ASSOCIATED colloids and not Macromolecular colloids.

Answer key and solution verified before publishing.

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Exam: JEE Advanced 2021
Paper: Paper 1
Subject: Chemistry
Chapter: Surface Chemistry
Topic: Colloids, emulsion and surfactant + Miscellaneous problems