Concept:Synthetic polyamides (like Nylon-6,6) are created via step-growth condensation polymerization of two different difunctional monomers.
Formula:$$ n\text{HOOC-(CH}_2\text{)}_4\text{-COOH} + n\text{H}_2\text{N-(CH}_2\text{)}_6\text{-NH}_2 \rightarrow \text{[-CO-(CH}_2\text{)}_4\text{-CO-NH-(CH}_2\text{)}_6\text{-NH-]}_n + 2n\text{H}_2\text{O} $$
Solution:- Nylon-6,6 is synthesized from two monomers: adipic acid (hexanedioic acid) and hexamethylenediamine (1,6-diaminohexane).
- Both monomers contain 6 carbon atoms, hence the name "6,6".
- Water is eliminated during bond formation, making it a condensation polymer of hexandioic acid & 1,6-diaminohexane. (While D is technically true, A is the most specific and accurate description).
Why other options are incorrect:Addition polymers form without the loss of small molecules (e.g., polyethylene). Nylon contains amide bonds (\( \text{-CO-NH-} \)), so it is a polyamide, not a polyester.
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