# State the intermolecular forces of polyamides and polyesters respectively

$\begin{array}{1 1}(a)\;\text{hydrogen bonding & hydrogen bonding }\\(b)\; \text{dipole-dipole interaction & dipole-dipole interaction}\\(c)\;\text{dipole-dipole interaction & hydrogen bonding}\\(d)\;\text{hydrogen bonding & dipole-dipole interaction}\end{array}$

In case of polyamides (such as nylon),the intermolecular forces are hydrogen bonding while in polyesters(such as terylene,dacron, etc),the inter molecular forces are dipole-dipole interactions between polar carbonyl $(C=O)$ and amine $(-NH)$ groups.
Hence (d) is the correct answer.