Question

Among the following, the surfactant that will form micelles in aqueous solution at the lowest molar concentration at ambient condition is : -
(a) CH₃(CH₂)₁₅N⁺(CH₃)₃Br⁻
(b) CH₃(CH₂)₁₁O$SO^-_3$Na⁺
(c) CH₃(CH₂)₆COO⁻Na⁺
(d) CH₃(CH₂)₁₁N⁺(CH₃)₃Br⁻

Answer 1

Answer:(d) CH₃(CH₂)₁₁N⁺(CH₃)₃Br⁻ is the correct answer.

Explanation:

Surfactant is the substance which reduces surface tension of the liquid.

Micellles are lipid molecules in the colloidal solutions.

They are in equilibrium with the solution.

They contain more than 100 molecules.

Here, (d) CH₃(CH₂)₁₁N⁺(CH₃)₃Br⁻ is correct because

If the size of hydrophobic chain is more the solubility will be less.

The process of surfactant mixing with the micellles will also increase.

Thus option (d) CH₃(CH₂)₁₁N⁺(CH₃)₃Br⁻ has biggest chain and thus it is the correct answer.

Answer 2

$\bold{CH₃(CH₂)₁₁N⁺(CH₃)₃Br⁻}$