Question

Identify the functional group in the following detergent molecule $C{{H}_{3}}-{{\left( C{{H}_{2}} \right)}_{10}}-C{{H}_{2}}OS{{O}_{3}}^{-}N{{a}^{+}}$

Answer 1

Hint: The detergent molecule has two important ends which are vital and responsible for the properties of the detergent molecule. The constituents of the detergent molecules describe much about their chemical terms and other properties.

Complete answer:
Let us learn about the detergents and some other terms related to the same;
Detergents- Detergents are the formulated products of either sodium salts of alkyl hydrogen sulfate or sodium salts of long chain alkyl benzene sulphonic acids. They are superior to soaps.
In short, they are the cleansing agents that combine with impurities and dirt molecules and remove them from the surfaces. There are three types of detergents;
1. Anionic detergents- They have anions at the soluble ends of the chains. They are the sodium salts of sulphonated long chains of hydrocarbons or alcohols. For example, n-dodecyl benzene and sodium lauryl sulphate.
2. Cationic detergents- They have cations at the soluble ends of the chains. They are the quaternary ammonium salts of amines with chlorides, acetates or bromides. For example, cetyltrimethylammonium chloride.
3. Non-ionic detergents- They have hydrogen bonding at the soluble ends of the chains. These detergents are either monoesters of polyhydric alcohols or polyethers derived from ethylene oxide. For example, pentaerythrityl stearate.
Mechanism of cleaning-
A molecule of detergent has two ends i.e. a long chain of hydrocarbon tail soluble in oil (hydrophobic end) and head soluble in water (hydrophilic end).
Thus, now according to the given illustration;
We have a molecule of sodium lauryl sulphate; anionic detergent with the formula $C{{H}_{3}}-{{\left( C{{H}_{2}} \right)}_{10}}-C{{H}_{2}}OS{{O}_{3}}^{-}N{{a}^{+}}$.
As we know, hydrocarbon part is hydrophobic in nature which is $C{{H}_{3}}-{{\left( C{{H}_{2}} \right)}_{10}}-C{{H}_{2}}-$ and the functional group is hydrophilic in nature i.e. $-S{{O}_{4}}^{2-}$

Therefore, the functional group in $C{{H}_{3}}-{{\left( C{{H}_{2}} \right)}_{10}}-C{{H}_{2}}OS{{O}_{3}}^{-}N{{a}^{+}}$ molecule is $-S{{O}_{4}}^{2-}$.

Note: Do note that the mechanism of cleansing action by detergent and soap are the same, though they differ in their respective properties and methods of preparation.