(i) Nylon-6

(ii) Nylon-6, 6

 $$\text{n}{\text{H}}_2\text{N}{({\text{CH}}_2)}_6{\text{NH}}_2+\text{n}\text{HOOC}{({\text{CH}}_2)}_4\text{COOH}\to —\underset{\text{Nylon}6,6}{[\text{NH}{({\text{CH}}_2)}_6}\text{NHCO}{({\text{NH}}_2)}_4\text{CO}{]}_{\text{n}}—+{\text{nH}}_2\text{O}$$

(iii) Polythene

 $\begin{array}{l}\text{n}\text{C}{\text{H}}_2=\text{C}{\text{H}}_2\underset{}{\overset{\text{P}\text{o}\text{l}\text{y}\text{m}\text{e}\text{r}\text{i}\text{s}\text{a}\text{t}\text{i}\text{o}\text{n}}{\to }}—{\left[\text{C}{\text{H}}_2-\text{C}{\text{H}}_2\right]}_{\text{n}}—\\ \text{E}\text{t}\text{h}\text{e}\text{n}\text{e}\text{P}\text{o}\text{l}\text{y}\text{t}\text{h}\text{e}\text{n}\text{e}\end{array}$