$X$ is HDP and $Y$ is LDP.

$X$ is LDP and $Y$ is HDP.

$X$ is used in the preparation of flexible pipes and $Y$ is used in manufacturing squeeze bottles.

$X$ is used in insulation of electricity carrying wires, $Y$ is used in manufacturing of bottles.

$\mathrm{HO}-\mathrm{CH}_2-\mathrm{CH}_2-\mathrm{OH}$

$\mathrm{CH}_3-\mathrm{OH}$

Low density polythene

Telfon

Polyacrylonitrile

High density polythene