Question

Among the following, the surfactant that will form micelles in aqueous solution at the lowest molar concentration at ambinent condition is:

• A. $C{H}_3\left(C{H}_2{)}_{15}{N}^{+}\right(C{H}_3{)}_{3}B{r}^{-}$
• B. $C{H}_3(C{H}_2{)}_{11}OS{O}_{3^{-}}N{a}^{+}$
• C. $C{H}_3(C{H}_2{)}_{6}CO{O}^{-}N{a}^{+}$
• D. $C{H}_3\left(C{H}_2{)}_{11}{N}^{+}\right(C{H}_3{)}_{3}B{r}^{-}$

Answer 1

The correct option is A $C{H}_3\left(C{H}_2{)}_{15}{N}^{+}\right(C{H}_3{)}_{3}B{r}^{-}$

The larger the hydrophobic fragment of surfactant, easier it is to form the micelles and smaller will be the critical micelle concentration.
Therefore, $C{H}_3\left(C{H}_2{)}_{15}{N}^{+}\right(C{H}_3{)}_{3}B{r}^{-}$will have the lowest critical micelle concentration.

Hence, the correct option is A.