Question

Assertion (A): The formation of micelles takes place only above a

particular concentration called critical micelle

concentration (CMC).

Reason (R): The conductivity of a solution decreases sharply at the

CMC. ​

Answer 1

Answer:

B

Explanation:

There are some substances which at low concentrations behave as normal strong electrolytes but at higher concentrations exhibit colloidal behaviour due to the formation of aggregated particles. The aggregated particles thus formed are called micelles. These are also known as associated colloids.

The formation of micelles takes places only above a particular temperature called Kraft temperature (T k )and above a particular concentration called critical micelle concentration (CMC).

Each micelle contains at least 100 molecules. Therefore, conductivity of the solution decreases sharply at the CMC as number of ions decreases due to aggregation.