Question

Which part of soap $\left(RCO{O}^{-}\right)$ dissolves grease and forms micelle?

• A. $R$ part (called tail of the anion)
• B. $CO{O}^{-}$ part (called head of the anion)
• C. Both $A$ and $B$
• D. None of the above

Answer 1

The correct option is A $R$ part (called tail of the anion)

In colloids, critical micelle concentration (CMC) is the concentration of surfactants above which micelles form and all additional surfactants added to the system go to micelles. CMC depends on chain length.

The greater is the chain length of the hydrocarbon tail, smaller is the CMC. So, the alkyl hydrocarbon chain dissolves grease and forms micelles since it forms the non-polar part.