Nylon 6, 6 is obtained by condensation polymerisation of

adipic acid and hexamethylenediamine

The correct answer is 2. adipic acid and hexamethylenediamine.

Nylon 6,6 is a condensation polymer that is formed by the reaction of adipic acid and hexamethylenediamine. The two monomers react to form a polyamide, which is a type of polymer that contains both amide and amine groups. The condensation reaction produces water as a byproduct.

Ethylene glycol and terephthalic acid are the monomers used to make nylon 6, which is a different type of nylon. Adipic acid and phenol are not used to make nylon.

Here is the reaction for the condensation polymerization of adipic acid and hexamethylenediamine to form nylon 6,6:

The product of the reaction is a long, chain-like molecule with amide and amine groups alternating along the chain. This molecule is called nylon 6,6.