Question

Nylon is an example of:
(A) Polyester
(B) Polysaccharide
(C) Polyamide
(D) Polythene

Answer 1

Hint: The monomers of nylon are an acid and an amine. The bonds which join these monomeric units are similar to the peptide bonds chemically.

Complete step by step solution:
Let’s get to know about nylon in a bit more detail:
- Nylon forms when multiple units of both hexamethylene diamine ($N{{H}_{2}}{{(C{{H}_{2}})}_{6}}N{{H}_{2}}$) and adipic acid ($COOH{{(C{{H}_{2}})}_{4}}COOH$ ) react with each other.
- Nylon is a synthetic polymer. Its constituents and the process of preparation are completely artificial in nature, which means they do not have any similar natural counterparts.
- In the formation of nylon, water is eliminated at the bonding between its constituent molecules which undergo a condensation-polymerization reaction. It is therefore a type of condensation polymer. The reaction is as follows:

\[nN{{H}_{2}}{{(C{{H}_{2}})}_{6}}N{{H}_{2}}+nCOOH{{(C{{H}_{2}})}_{4}}COOH\xrightarrow{Polymerization}{{[-NH{{(C{{H}_{2}})}_{6}}NHCO{{(C{{H}_{2}})}_{4}}CO-]}_{n}}+n{{H}_{2}}O\]

- Nylon is a type of synthetic fibre. It is known for its high tensile strength.
As nylon is formed from the combination of an amine and acid it is therefore chemically an amide. The general reaction is as follows:
     \[RN{{H}_{2}}+R'COOH\rightleftharpoons R'CO{{O}^{-}}N{{H}_{3}}^{+}R\xrightarrow{\Delta }R'CONHR+{{H}_{2}}O\]
Hence the answer to the above question is (C) Polyamide. We discuss the other options below:
- A polyester as mentioned in option (A) is only formed when multiple units of an alcohol combine with that of an acid in acidic or basic conditions.
- A polysaccharide as mentioned in option (B) is only formed by repeating units of monosaccharides or disaccharides.
- A polythene as mentioned in option (D) is only formed from repeating units of ethene.

So, the correct answer is “Option D”.

Note: In questions like these, the chemical nature of the monomers is more important than the polymer itself. As you saw above, when monomers having different functional groups react together they form a compound that is both chemically and physically unlike the parent molecules. Knowledge of the monomeric chemical structure is therefore crucial.