Polymers

All the given statements are correct i.e. $A, B, C$.

Glyptal is made from monomer ethylene glycol and phthalic acid.

• Bakelite is used in making combs, phonograph records, electrical switches and handles of utensils etc.

• Nylon-2-nylon-6 is an alternating polyamide copolymer of glycine and amino caproic acid.

It is a biodegradable polymer.

$ \begin{aligned} &\text { Weight average molecular mass }\\ &\begin{aligned} & \left(\bar{M}_w\right)=\frac{\Sigma n_i m_i^2}{\Sigma n_i m_i} \\ & =\frac{3 \times\left(10^3\right)^2+3 \times(500)^2+4 \times(200)^2}{3 \times 10^3+3 \times 500+4 \times 200} \\ & =\frac{3,000,000+7,50,000+1,60,000}{5300} \\ & =737.7 \end{aligned} \end{aligned} $

The correct match is A-III, B-I, C-IV, D-II.

Bakelite is a polymer made up of monomers, phenol and formaldehyde.

Natural rubber is a polymer made up of monomers 2 -methyl-1,3-butadiene.

Glyptal is formed from monomeric units phthalic acid and ethylene glycol.

Nylon-2-nylon-6 is formed from glycine and aminocaproic acid monomers.

Let's analyze the list one by one to identify which ones are elastomers:

$\textbf{Natural rubber}$ – It is a classic elastomer, mainly composed of cis-1,4-polyisoprene.

$\textbf{Polyethene}$ – This is a thermoplastic polymer, not known for rubber-like elasticity.

$\textbf{Vulcanized rubber}$ – Vulcanization is a process applied to rubber (often natural rubber) to enhance its elasticity and strength, so it remains an elastomer.

$\textbf{Bakelite}$ – This is a thermosetting plastic, not an elastomer.

$\textbf{Polyvinylchloride (PVC)}$ – Typically a thermoplastic, it does not exhibit the high elasticity characteristic of elastomers.

$\textbf{Buna-N}$ – Also known as nitrile rubber, it is a synthetic elastomer commonly used for its oil resistance.

$\textbf{Nylon-6}$ – A polyamide that is a thermoplastic, not classified as an elastomer.

$\textbf{Neoprene}$ – Another synthetic rubber well known for its elastic properties, making it an elastomer.

From the list, the elastomers are:

Natural rubber

Vulcanized rubber

Buna-N

Neoprene

Thus, there are 4 elastomers.

The correct answer is: Option A (4).

Starch, Protein, Rubber are natural polymer.

Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products.

Melamine polymer is formed by the condensation polymerization of melamine and formaldehyde.

Buna – N is synthetic rubber which can be stretched and retains its original status on releasing the force.

A copolymer is a polymer that consists of two or more different types of monomers.

Here are the options examined:

• Option A: Buna-S - It's a copolymer of butadiene and styrene.


• Option B: Neoprene - It is made from the polymerization of chloroprene, so it is a homopolymer, not a copolymer.


• Option C: PHBV - Polyhydroxybutyrate-co-valerate (PHBV) is a copolymer consisting of Polyhydroxybutyrate (PHB) and Polyhydroxyvalerate (PHV).


• Option D: Butadiene-styrene - This is another name for SBR, or styrene-butadiene rubber, and it's a copolymer of butadiene and styrene.

Therefore, the correct option is (A).

(A) Polymerization of chloroprene gives synthetic rubber.

(B) Teflon is manufactured by heating tetrafluoroethene with a free radical or persulphate catalyst at hight pressure.

(C) Polyvinyl chloride (PVC) is a thermoplastic polymer and used in making hand bags, vinyl flooring and water pipes.

(D) Ethene at 350-570 K temperature and 1000-2000 atm pressure in the presence of a peroxide initiator yields low density polythene.

Preparation of polyethylene is done in the presence of the "Zeigler-Natta catalyst" which is a mixture of trimethylaluminium $\left[\mathrm{Al}\left(\mathrm{CH}_3\right)_3\right]$ and titanium tetrachloride $\left(\mathrm{TiCl}_4\right)$.

Buna-S is the co-polymer of but 1, 3-diene and styrene as follows.

Styrene butadiene rubber is also called buna-S, in which ‘Bu’ stands for butadiene, ‘na’ stands for sodium and ‘S’ stands for styrene.

Since, butadiene and styrene is one of the constituent monomer of given polymer.

Monomer is a molecule that forms the basic unit of polymer. These are building blocks of a polymer. Monomers bind to other monomer to form the repeating chain molecules. The monomers may be either natural or synthetic in origin monomer of melamine are,

$ \text { Hence, option (c) is the correct answer. } $

It is PHBV , i.e. poly- $\beta$-hydroxy butyrate-co- $\beta$-hydroxy valerate. It is a condensation, biodegradable and thermoplastic polyester (copolymer). So, statements I, II and IV are correct.

$\because$ Buna- S is $n \mathrm{CH}_2=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}_2$

(1, 3-butadine) $+n \mathrm{C}_6 \mathrm{H}_5-\mathrm{CH}=\mathrm{CH}_2$ (styrene);

Buna- N is $n \mathrm{CH}_2=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}_2$

All these are synthetic rubber.

Hence, option (c) is the correct answer, i.e. (ii), (iii) and (iv).

Anionic polymerisation can anionic initiator generates a carbanionic intermediate and such polymerisation is termed anionic addition polymerisation.

In this case, the active centre of propagating species has negative charge. So, it takes place easily with the monomer having electron withdrawing groups such as phenyl, nitrile etc. that are capable of stabilising the propagating species. Hence, $\mathrm{CH}_2=\mathrm{CH}-\mathrm{CN}$ is the most reactive towards anionic polymerisation.