Among the following, which surfactant will form micelles in aqueous solution at the lowest molar concentration at ambient conditions?

Options

A. `CH_(3)(CH_(2))_(11)OSO_(3)^(-)Na^(+)`
B. `CH_(3)(CH_(2))_(15)N^(+)(CH_(3))_(3)Br^(-)`
C. `CH_(3)(CH_(2))_(6)COO^(-)Na^(+)`
D. `CH_(3)(CH_(2))_(11)N^(+)(CH_(3))_(3)Br^(-)`

Answer

B

Explanation

Critical concentration for micelles formation decreases as the molecular mass of hydrocarbon chain of surfactant grows because in this case true solubility diminishes and the tendency of surfactant molecules to associate increases i.e., more the hydrocarbon part, lesser the concentration.