Question

Critical Micelle concentration for a soap solution is $1.5\times {10}^{-4}mol{L}^{-1}.$ Micelle formation is possible only when the concentration of soap solution in $mol{L}^{-1}$ is

• A. $2.0\times {10}^{-3}$
• B. $4.6\times {10}^{-5}$
• C. $7.5\times {10}^{-5}$
• D. $1.1\times {10}^{-4}$

Answer 1

The correct option is A $2.0\times {10}^{-3}$

Some substances at low concentration behaves as a normal electrolytes but at higher concentration exhibit colloidal behavior due to formation of micelles.
For micelle formation, the concentration of the soap solution needs to be higher than the CMC, which happens only in the option where the concentration is $2.0\times {10}^{-3}$