High density polyethylene $(HDPE)$ can be prepared from ethylene by

Identify the monomers used to prepare novolac.

Match the polymers given in column $-I$ with the preferred mode of polymerisation followed by their monomers in column $-II$.

Column $-I$	Column $-II$
$A$. Nylon $-6, 6$	$i$. Free radical polymerisation
$B$. $PVC$	$ii$. Ziegler-Natta polymerization or coordination polymerization
$C$. $HDP$	$iii$. Anionic polymerisation
	$iv$. Condensation polymerization

The correct functional group $X$ and the reagent/reaction conditions $Y$ in the following scheme are:
$X-(CH_2)_4-X \xrightarrow{Y} \text{condensation polymer}$
$(i) \text{ with } HOOC-(CH_2)_4-COOH / \text{heat}$
$(A) X = COOCH_3, Y = H_2 / Ni / \text{heat}$
$(B) X = CONH_2, Y = H_2 / Ni / \text{heat}$
$(C) X = CONH_2, Y = Br_2 / NaOH$
$(D) X = CN, Y = H_2 / Ni / \text{heat}$

How is a linear chain polymer formed?

The thermosetting polymer Bakelite is formed by the reaction of phenol with which of the following?