Classification of Polymer Questions in English

(A) Polyamides and polyesters are two groups of synthetic fibres that possess high tensile strength,are not easily stretched,and are widely used in the textile industry.
Polyvinyl chloride is a synthetic plastic polymer,and neoprene is a synthetic rubber.
Therefore,polyester is an example of a fibre.
Hence,option $(A)$ is correct.

(D) Teflon is a polymer of tetrafluoroethene $(CF_2=CF_2)$.
It is formed by the polymerization of tetrafluoroethene monomers without the loss of any small molecules.
Therefore,it is classified as an addition polymer.

(A) Synthetic polymers are human-made polymers,such as polythene,$PVC$,and nylon $6, 6$.
Semi-synthetic polymers are derived from naturally occurring polymers by chemical modification,such as cellulose nitrate and rayon (cellulose acetate).
In the given options,Polythene is a synthetic polymer $(X)$ and Rayon is a semi-synthetic polymer $(Y)$.

(C) Thermoplastic polymers are those that soften on heating and harden on cooling,such as Polystyrene.
Thermosetting polymers are those that undergo extensive cross-linking during molding and become infusible,such as Bakelite.
Therefore,$X = \text{Polystyrene}$ and $Y = \text{Bakelite}$.

(D) Addition polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds. $A$ homopolymer is formed from only one type of monomer unit.
$1$. Polythene is formed from ethene $(CH_2=CH_2)$.
$2$. Teflon (Polytetrafluoroethene) is formed from tetrafluoroethene $(CF_2=CF_2)$.
$3$. Orlon (Polyacrylonitrile) is formed from acrylonitrile $(CH_2=CH-CN)$.
All three are addition homopolymers. Therefore,the correct set is Polythene,Teflon,and Orlon.

(D) Condensation polymers are formed by repeated condensation reactions between two different bi-functional monomeric units, involving the elimination of small molecules such as water, alcohol, or hydrogen chloride.
$A$, $B$, and $C$ (Terylene, Nylon $6,6$, and Bakelite) are examples of condensation polymers.
Polystyrene is an addition polymer formed by the polymerization of styrene $(C_6H_5CH=CH_2)$ monomers without the elimination of any small molecules.

(A) Elastomers are polymers that have weak intermolecular forces of attraction, allowing them to be stretched.
These include: Natural rubber, vulcanized rubber, Buna-$N$, and Neoprene.
Therefore, there are $4$ elastomers in the given list.

(B) The correct matching is as follows:
$(A)$ Fibre: $(IV)$ Dacron
$(B)$ Elastomer: $(III)$ Neoprene
$(C)$ Thermosetting polymer: $(I)$ Bakelite
$(D)$ Thermoplastic polymer: $(II)$ Polystyrene
Therefore, the correct sequence is $A-IV, B-III, C-I, D-II$.

(A) semi-synthetic polymer is derived from a naturally occurring polymer through chemical modification.
Starch and rubber are natural polymers, while nylon-$6, 6$ is a synthetic polymer.
Cellulose acetate is prepared by the acetylation of cellulose, which is a natural polymer.
Therefore, the reaction is: $Cellulose \xrightarrow{\text{Acetylation}} Cellulose \ acetate$ (Natural polymer $\rightarrow$ Semi-synthetic polymer).

(B) The schematic illustrations represent the structures of different types of polymers:
$(A)$ shows a cross-linked polymer structure, which is characteristic of thermosetting polymers like Bakelite.
$(B)$ shows linear polymer chains, which is characteristic of high-density polyethylene $(HDPE)$.
$(C)$ shows branched polymer chains, which is characteristic of low-density polyethylene $(LDPE)$.

(D) Natural polymers are those that occur naturally in plants and animals.
Silk, cotton, and proteins are all examples of natural polymers.
Bakelite, polystyrene, neoprene, nylon, terylene, and $PVC$ are synthetic polymers.

(A) copolymer is a polymer formed from two or more different types of monomer units.
Option $A$ represents Buna-$S$ (Styrene-Butadiene Rubber), which is formed by the copolymerization of $1,3$-butadiene $(CH_2=CH-CH=CH_2)$ and styrene $(C_6H_5CH=CH_2)$.
Options $B$, $C$, and $D$ represent homopolymers:
$B$ is Polytetrafluoroethene (Teflon),
$C$ is Polychloroprene (Neoprene),
$D$ is Polyvinyl chloride $(PVC)$.
Therefore, the correct answer is $A$.

(B) Polymers which control various life processes in plants and animals are called biopolymers.
Cellulose, Insulin, $DNA$, starch, and proteins are examples of biopolymers.
Nylon-$6$ is a synthetic polymer, not a biopolymer.

(D) The classification of polymers based on molecular forces is as follows:
$A$. Fibre: These have strong intermolecular forces like hydrogen bonding. Example: Nylon-$6$, $6$ $(I)$.
$B$. Elastomer: These have weak intermolecular forces allowing stretching. Example: Neoprene $(II)$.
$C$. Thermosetting polymer: These are cross-linked polymers that become hard on heating. Example: Bakelite $(III)$.
$D$. Thermoplastic polymer: These soften on heating and harden on cooling. Example: Polyvinyl chloride $(IV)$.
Therefore, the correct matching is $A-I, B-II, C-III, D-IV$.

(C) The number average molecular mass $(M_n)$ is calculated using the formula: $M_n = \frac{\sum N_i M_i}{\sum N_i} = \frac{N_1 M_1 + N_2 M_2 + N_3 M_3}{N_1 + N_2 + N_3}$.
Given: $N_1 = 50, M_1 = 5,000$; $N_2 = 100, M_2 = 10,000$; $N_3 = 50, M_3 = 15,000$.
Substituting the values: $M_n = \frac{(50 \times 5,000) + (100 \times 10,000) + (50 \times 15,000)}{50 + 100 + 50}$.
$M_n = \frac{250,000 + 1,000,000 + 750,000}{200} = \frac{2,000,000}{200} = 10,000$.
Thus, the number average molecular mass is $10,000$.

(C) $Dacron$ is a condensation polymer. It is also known as $Terylene$.
It is a polymer obtained by the condensation reaction between $Ethylene \ glycol$ and $Terephthalic \ acid$ at $420-460 \ K$ in the presence of a zinc acetate-antimony trioxide catalyst.
The reaction is as follows:
$nHOCH_2CH_2OH + nHOOC-C_6H_4-COOH \xrightarrow{420-460 \ K} [-O-CH_2CH_2-O-CO-C_6H_4-CO-]_n + 2nH_2O$

(A) co-polymer is a polymer formed from two or more different types of monomer units.
$Buna-S$ is a co-polymer formed by the polymerisation of $1,3-butadiene$ and styrene.
The structure of $Buna-S$ is: $(-CH_2-CH=CH-CH_2-CH(C_6H_5)-CH_2-)_n$.
Teflon, $PVC$, and Polypropylene are homopolymers.

(A) $Buna-S$ is a copolymer of $1,3-butadiene$ and $styrene$.
It possesses weak intermolecular forces of attraction between the polymer chains, which allows the polymer to be stretched.
Polymers that have weak van der Waals forces and can be stretched like rubber are classified as elastomers.
Therefore, $Buna-S$ is an example of an elastomer.

(B) Natural rubber is a polymer of $isoprene$ $(2-methyl-1,3-butadiene)$.
It possesses weak intermolecular forces of attraction, such as van der Waals forces, which allow the polymer chains to be stretched.
Due to these weak forces, it can return to its original shape after being stretched, which is the characteristic property of an elastomer.
Therefore, natural rubber is classified as an elastomer.

(B) $1$. Chain growth polymers are formed by the addition of monomer units containing double or triple bonds without the loss of any small molecules.
$2$. $Teflon$ (polytetrafluoroethene) is formed by the addition polymerization of tetrafluoroethene $(CF_2=CF_2)$, which is a chain growth process.
$3$. $Nylon-6$, $Nylon-66$, and $Terylene$ are step growth (condensation) polymers formed by the loss of small molecules like $H_2O$ or $CH_3OH$.

(B) Polymers are classified based on several criteria such as:
$(1)$ Source (Natural, Synthetic, Semi-synthetic)
$(2)$ Structure (Linear, Branched, Cross-linked)
$(3)$ Method of polymerization (Addition, Condensation)
$(4)$ Molecular forces (Elastomers, Fibres, Thermoplastics, Thermosetting polymers)
$(5)$ Number of monomers is not a standard criterion for the classification of polymers. Therefore, option $B$ is the correct answer.

(A) $1$. $A$ homopolymer is a polymer formed from only one type of monomeric unit.
$2$. Polyacrylonitrile is formed by the polymerization of acrylonitrile $(CH_2=CH-CN)$ units only, hence it is a homopolymer.
$3$. Buna-$N$ is a copolymer of $1,3$-butadiene and acrylonitrile.
$4$. Urea formaldehyde resin is a copolymer of urea and formaldehyde.
$5$. Polycarbonate is a copolymer formed from bisphenol-$A$ and phosgene.
$6$. Therefore, Polyacrylonitrile is the correct answer.

(A) $1$. The given polymer $[NH - (CH_2)_5 - CO]_n$ is Nylon-$6$, which is a condensation polymer formed from caprolactam.
$2$. Teflon $(CF_2=CF_2)_n$, Polyacrylonitrile $(CH_2=CH-CN)_n$, and $LDP$ (Low Density Polyethylene) are formed by addition polymerization.
$3$. However, the question asks to identify which of the options is an addition polymer. Among the choices, Teflon, Polyacrylonitrile, and $LDP$ are all addition polymers. Given the structure provided in the question is Nylon-$6$ (a condensation polymer), the question likely asks for an addition polymer from the list. All options $A$, $B$, and $C$ are addition polymers. Assuming the question asks for a standard example of addition polymerization, Teflon is a primary example.

(D) $1$. Addition polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds without the loss of any small molecules.
$2$. $Teflon$, $Polyacrylonitrile$, and $LDP$ $(Low Density Polyethylene)$ are all addition polymers.
$3$. $PHBV$ $(Poly \beta-hydroxybutyrate-co-\beta-hydroxyvalerate)$ is a biodegradable aliphatic polyester, which is formed by condensation polymerisation of $3-hydroxybutanoic$ acid and $3-hydroxypentanoic$ acid.
$4$. Therefore, $PHBV$ is not obtained by addition polymerisation.

(B) Step $1$: Identify the structure of the given polymers.
Step $2$: High density polyethylene $(HDPE)$ is a linear polymer.
Step $3$: Low density polyethylene $(LDPE)$ is formed by free radical polymerization under high pressure, resulting in a highly branched structure.
Step $4$: $PVC$ and Melamine are generally linear or cross-linked polymers.
Step $5$: Therefore, $LDPE$ is the correct example of a branched-chain polymer.