Answer: Option D. -> Urea-formaldehyde resins
:
D
Polythene, Polyvinyls and Polystyrene are Thermoplastic polymers.
Urea-formaldehyde resin is a thermosetting polymer.

Answer: Option D. -> Bakelite
:
D
A’ is Novolac, ‘B’ is Bakelite

Answer: Option D. -> Bakelite
:
B
$P.D.I=\frac{\overline{M_W}}{\overline{M_n}}=\frac{40000}{30000}=1.33$

Answer: Option C. -> Neoprene
:
C

Synthetic Rubber is Manufactured using neoprene.

Answer: Option A. -> Formaldehyde
:
A
Melamine and formaldehyde are starting materials for this intermediate. Its polymerisation gives melamine polymer.

Answer: Option B. -> Novolac
:
B
A’ is novolac, ‘B’ is Bakelite. Novolac is a phenol-formaldehyde resin with a formaldehyde to phenol molar ratio of less than one.

Answer: Option A. -> Ziegler-Natta process
:
A
HDPE ispreparedbyco-ordination polymerization whichoccursthroughtheintermediateformationofco-ordinationcomplexes.Forexample,ethylenefirstformsaco-ordinationcomplex with the transition metal titanium by donating its $\pi$ electrons. The $\pi$ complex thus formed then reacts stepwise with a large number of ethylene moleculesultimately leading to the formation of a polymer. The polythene so obtained has high density $\left(0.92g/c{m}^3\right)$ and higher m.pt.(403K)ascompareto LDPE$(density-0.92g/c{m}^{3}andm.pt.384K)$

Answer: Option B. -> (i) - (d), (ii)-(a), (iii) - (b)
:
B

Answer: Option C. -> Ziegler-Natta catalyst
:
C
Zirgler-Natta catalyst $(C_2{H}_5{)}_{3}Al+TiC{l}_4$

Answer: Option D. -> Both (a) and (b) are correct
:
D
$\text{Vulcanised rubber}\to \text{Sulphur cross-links present.}$

$\text{Melamine}\to \text{Type of cross-links or network polymers.}$