Composition, Properties and Uses of Polymer Questions in English

(D) $1$. $\text{Buna-}S$ is a copolymer formed from $1,3\text{-butadiene}$ and styrene. Hence,$A$ is correct.
$2$. $\text{Nylon-}6,6$ is a condensation polymer formed by the reaction of adipic acid and hexamethylenediamine. Hence,$B$ is correct.
$3$. $\text{Nylon-}6,6$ possesses high tensile strength and is classified as a fibre. Hence,$C$ is correct.
$4$. $\text{Terylene}$ (Dacron) is a polyester fibre,not a thermosetting polymer. Hence,$D$ is incorrect.
$5$. $\text{Buna-}N$ is a copolymer of $1,3\text{-butadiene}$ and acrylonitrile,not a homopolymer. Hence,$E$ is incorrect.
Therefore,the correct statements are $A$,$B$,and $C$.

(C) Buna-$N$ is a synthetic rubber.
It is obtained by the copolymerization of $1, 3-$butadiene and acrylonitrile in the presence of a peroxide catalyst.
The $N$ in Buna-$N$ stands for acrylonitrile.

(A) . Bakelite is a thermosetting polymer used for making electrical switches $(A-II)$.
$B$. Glyptal is used in the manufacture of paints and lacquers $(B-III)$.
$C$. $PVC$ (Polyvinyl chloride) is used in the manufacture of water pipes,raincoats,and handbags $(C-IV)$.
$D$. Polystyrene is used in the manufacture of radio and television cabinets $(D-I)$.
Therefore,the correct matching is $A-II, B-III, C-IV, D-I$.

(C) Natural rubber is a linear polymer of isoprene $(2\text{-methyl-}1,3\text{-butadiene})$ and is also called $cis\text{-}1,4\text{-polyisoprene}.$
It possesses elastic properties due to its coiled structure.
The $cis\text{-polyisoprene}$ molecules consist of various chains held together by weak van der Waals interactions,not strong polar interactions.
Therefore,Assertion $(A)$ is true,but Reason $(R)$ is false.

(A) Dacron (also known as Terylene) is a condensation polymer formed by the polymerization of ethylene glycol $(HO-CH_2-CH_2-OH)$ and terephthalic acid $(HOOC-C_6H_4-COOH)$.
Since the linkage formed between the monomers is an ester linkage $(-COO-)$,it is classified as a polyester polymer.
Thus,Assertion $A$ is correct because Dacron is indeed a polyester.
Reason $R$ is also correct as it correctly identifies the monomers involved in the synthesis of Dacron.
Furthermore,Reason $R$ provides the correct explanation for Assertion $A$ because the presence of ester linkages resulting from the condensation of these specific monomers defines it as a polyester.

(C) Polymers that can be stretched and return to their original shape upon the release of force are known as elastomers.
$Buna-N$ is a synthetic rubber,which is an elastomer.
Therefore,it can be stretched and retains its original status on releasing the force.

(B) $Nylon\,6,6$ is used for $Bristles\,of\,brushes$ $(A-I)$.
$Low\,density\,polythene$ is used for $Toys$ $(B-II)$.
$High\,density\,polythene$ is used for $Buckets$ $(C-III)$.
$Teflon$ is used for $Non-stick\,utensils$ $(D-IV)$.
Therefore,the correct matching is $A-I, B-II, C-III, D-IV$.

(C) Vulcanization is a process of heating raw rubber with sulphur to improve its physical properties,such as elasticity and strength.
Natural rubber is a polymer of $isoprene$ $(2-methyl-1,3-butadiene)$.
Therefore,vulcanization of rubber is carried out by heating a mixture of $isoprene$ (or natural rubber) and $sulphur$.

(A) The correct matches are as follows:
$(A)$ Neoprene is a polymer of chloroprene $(2-chloro-1,3-butadiene)$. Thus,$A-II$.
$(B)$ Teflon is a polymer of tetrafluoroethene $(CF_2=CF_2)$. Thus,$B-III$.
$(C)$ Acrilan (polyacrylonitrile) is a polymer of acrylonitrile $(CH_2=CH-CN)$. Thus,$C-I$.
$(D)$ Natural rubber is a polymer of isoprene $(2-methyl-1,3-butadiene)$. Thus,$D-IV$.
Therefore,the correct sequence is $A-II, B-III, C-I, D-IV$.

(B) The correct matches are as follows:
$A$. Phenol-formaldehyde resin (linear) is known as Novolac $(II)$.
$B$. Copolymer of $1,3$-butadiene and styrene is known as Buna-$S$ $(III)$.
$C$. Polyester of glycol and phthalic acid is known as Glyptal $(I)$.
$D$. Polyester of glycol and terephthalic acid is known as Dacron $(IV)$.
Therefore,the correct matching is $A-II, B-III, C-I, D-IV$.

(A) The given polymers are identified as follows:
$A$. $(-CH_2-C(Cl)=CH-CH_2-)_n$ is Neoprene,which is an elastomer $(III)$.
$B$. $(-NH-(CH_2)_6-NH-CO-(CH_2)_4-CO-)_n$ is Nylon-$6,6$,which is a fiber $(II)$.
$C$. $(-CH_2-CH(Cl)-)_n$ is Polyvinyl chloride $(PVC)$,which is a thermoplastic polymer $(IV)$.
$D$. $(-C_6H_3(OH)-CH_2-)_n$ is Novolac,which is a thermosetting polymer $(I)$.
Therefore,the correct matching is $A-III, B-II, C-IV, D-I$.

(A) . Polylactic acid is a biodegradable polymer.
It is a thermoplastic polyester.
It is obtained by the condensation polymerization of lactic acid.
The reaction is as follows:
$2CH_3CH(OH)COOH$ $\xrightarrow{-H_2O} \text{Lactide}$ $\xrightarrow{n} (-O-CH(CH_3)-CO-)_n$ (Polylactic acid).

(A) Nylon$-2-$nylon$-6$ is a biodegradable polyamide copolymer.
It is formed by the condensation polymerization of two monomers:
$1$. Glycine $(H_2N-CH_2-COOH)$
$2$. $6-$aminohexanoic acid $(H_2N-(CH_2)_5-COOH)$
Therefore,the correct option is $(A)$.

(B) Natural rubber is cis$-1,4-$polyisoprene,which has the structure: $(-CH_2-C(CH_3)=CH-CH_2-)_n$.
Upon complete hydrogenation,the double bonds in the polymer chain are saturated with hydrogen atoms.
The resulting structure is: $(-CH_2-CH(CH_3)-CH_2-CH_2-)_n$.
This structure is an alternating copolymer of ethylene $(-CH_2-CH_2-)$ and propylene $(-CH_2-CH(CH_3)-)$ units,commonly referred to as an ethylene-propylene copolymer.
Therefore,the correct option is $(B)$.

(B) The correct matches are as follows:
$A$. Glyptal is used in the manufacture of paints and lacquers $(A-III)$.
$B$. Neoprene is used for manufacturing gaskets and hoses $(B-IV)$.
$C$. Acrilan (polyacrylonitrile) is used as a substitute for wool in making synthetic blankets and sweaters $(C-II)$.
$D$. $LDP$ (Low Density Polyethylene) is used in the manufacture of squeeze bottles,toys,and flexible pipes $(D-I)$.
Therefore,the correct sequence is $A-III, B-IV, C-II, D-I$.

(A) Orlon is a synthetic fiber made from the polymer polyacrylonitrile.
It is formed by the addition polymerization of acrylonitrile monomer $(CH_2=CH-CN)$.
The reaction is as follows:
$n CH_2=CH-CN \xrightarrow{\text{Polymerisation}} [-CH_2-CH(CN)-]_n$
Thus,the polymer used in Orlon is polyacrylonitrile.

(D) . Nylon-$2$-nylon-$6$: Biodegradable polyamide polymer $(II)$
$B$. Buna-$N$: Copolymer of $1,3$-butadiene and acrylonitrile,which is a synthetic rubber $(III)$
$C$. Urea-formaldehyde: $A$ cross-linked thermosetting polymer $(I)$
$D$. Dacron: $A$ polyester polymer formed from ethylene glycol and terephthalic acid $(IV)$
Therefore,the correct matching is $A-II, B-III, C-I, D-IV$.

(A) Buna-$S$ is a copolymer formed by the polymerization of $1,3$-butadiene $(CH_2=CH-CH=CH_2)$ and styrene $(C_6H_5-CH=CH_2)$.
During the polymerization process,the double bonds rearrange to form a chain structure.
The correct repeating unit for Buna-$S$ is represented as $[-CH_2-CH=CH-CH_2-CH(C_6H_5)-CH_2-]_n$.

(B) Statement $I$ is false. The reaction of ethene in the presence of $AlEt_3$ and $TiCl_4$ (Ziegler-Natta catalyst) produces High Density Polyethene $(HDPE)$,not Low Density Polyethene $(LDP)$.
Statement $II$ is true. Caprolactam,when heated with water at $533-543 \ K$,undergoes ring-opening polymerization (a type of step-growth polymerization) to form Nylon-$6$.

(D) $a.$ Nylon-$6$ is prepared from the monomer Caprolactam $(III)$.
$b.$ Vulcanized rubber is a cross-linked polymer formed by heating rubber with sulphur $(II)$.
$c.$ cis-$1,4$-polyisoprene is the chemical name for Natural Rubber $(I)$.
$d.$ Polychloroprene is commonly known as Neoprene $(IV)$.
Therefore,the correct matching is $a$ $\rightarrow III, b$ $\rightarrow II, c$ $\rightarrow I, d$ $\rightarrow IV$.

(A) The correct matches are as follows:
$A$. Tetrafluoroethene is the monomer of Teflon $(III)$.
$B$. Acrylonitrile is the monomer of Orlon $(I)$.
$C$. Caprolactam is the monomer of Nylon-$6$ $(IV)$.
$D$. Isoprene ($2$-methyl-$1,3$-butadiene) is the monomer of Natural rubber $(II)$.
Therefore,the correct matching is $A-III, B-I, C-IV, D-II$.

(D) The strength of intermolecular forces in polymers follows the order: $\text{Fibers} > \text{Thermoplastics} > \text{Elastomers}$.
$1$. $\text{Nylon}$ is a fiber and has strong hydrogen bonding.
$2$. $\text{Cellulose}$ is a natural polymer with strong hydrogen bonding.
$3$. $\text{Poly(vinyl chloride)}$ is a thermoplastic with dipole-dipole interactions.
$4$. $\text{Natural rubber}$ is an elastomer held together by weak van der Waals forces.
Therefore,$\text{natural rubber}$ has the weakest intermolecular forces.

(A) Natural rubber is a polymer of isoprene ($2$-methyl-$1,3$-butadiene).
Its structure is $(CH_2-C(CH_3)=CH-CH_2)_n$.
On complete hydrogenation,the double bonds in the polymer chain are saturated with hydrogen atoms.
The resulting structure is $(CH_2-CH(CH_3)-CH_2-CH_2)_n$,which is identical to the structure of an ethylene-propylene copolymer.

(C) $(1)$ Natural rubber is cis-polyisoprene. Thus,statement $(1)$ is incorrect.
$(2)$ Nylon-$6$ is formed by the polymerization of caprolactam and contains amide linkages $(-NH-CO-)$. Thus,statement $(2)$ is correct.
$(3)$ Cellulose is a linear polymer of $\beta-D$-glucose units joined by $\beta$-glycosidic linkages. Thus,statement $(3)$ is incorrect.
$(4)$ Teflon is prepared by heating tetrafluoroethene $(CF_2=CF_2)$ in the presence of a persulphate catalyst at high pressure. Thus,statement $(4)$ is correct.
Therefore,statements $(2)$ and $(4)$ are correct.

(D) . Incorrect: The polymerization of chloroprene gives neoprene,not natural rubber. Natural rubber is a polymer of isoprene ($2$-methyl-$1,3$-butadiene).
$B$. Correct: Teflon is prepared by heating tetrafluoroethene with a free radical or persulphate catalyst at high pressures.
$C$. Correct: $PVC$ (polyvinyl chloride) is a thermoplastic polymer as it softens on heating and hardens on cooling.
$D$. Incorrect: Ethene at $350-570 \ K$ and $1000-2000 \ atm$ pressure in the presence of a peroxide initiator yields low density polythene $(LDPE)$,not high density polythene.

(B) Statement $I$ is true because cellulose contains a large number of hydroxyl $(-OH)$ groups,which form extensive hydrogen bonds with water,leading to higher water retention and longer drying times.
Statement $II$ is false because nylon is a synthetic polyamide with fewer sites for hydrogen bonding with water compared to the numerous hydroxyl groups present in cellulose-based cotton fibers.

(B) The formation of cellulose xanthate occurs in the viscose process for manufacturing rayon.
First,cellulose $(Cell-OH)$ reacts with $NaOH$ to form alkali cellulose $(Cell-ONa)$.
Then,alkali cellulose reacts with carbon disulfide $(CS_2)$ to form cellulose xanthate,which has the formula $Cell-O-C(=S)-SNa$.

(A) The $\omega$-amino caproic acid is a straight-chain amino acid with a total of $6$ carbon atoms,where the amino group $(-NH_2)$ is at the terminal $(\omega)$ position and the carboxylic acid group $(-COOH)$ is at the other end.
Caproic acid is a $6$-carbon carboxylic acid $(CH_3(CH_2)_4COOH)$.
Replacing the terminal hydrogen with an amino group gives $H_2N-(CH_2)_5-COOH$,which is $6$-aminohexanoic acid,commonly known as $\omega$-amino caproic acid.
Therefore,the correct formula is $H_2N-(CH_2)_5-COOH$.

(C) $PS$ (Polystyrene) is believed to leach styrene,which is a possible human carcinogen,into food when used as a household plastic.

(C) Biodegradable polymers are those that can be broken down by microorganisms in the environment.
Nylon $2-$nylon $6$ is a polyamide copolymer of glycine and amino caproic acid,which is biodegradable.
Nylon $6$,Nylon $6,6$,and $HDP$ (High Density Polyethylene) are synthetic polymers that are not biodegradable.

(D) Thermosetting polymers are cross-linked or heavily branched molecules that undergo extensive cross-linking in molds when heated,making them permanently hard and infusible.
$Bakelite$ (phenol-formaldehyde resin) is a classic example of a thermosetting polymer.
$Buna-S$ is an elastomer,while $Dacron$ and $Polyvinyls$ are thermoplastic polymers.

(B) is the correct answer.
Biodegradable polymers are those that can be decomposed by microorganisms.
Among the given options,$PHBV$ (Poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate) is a well-known biodegradable polymer.
$Teflon$,$LDP$ (Low Density Polyethylene),and Polyacrylonitrile are synthetic,non-biodegradable polymers.

(C) The given monomers are $1,3$-butadiene $(CH_2=CH-CH=CH_2)$ and acrylonitrile $(CH_2=CH-CN)$.
These monomers undergo copolymerization to form $B$üna-$N$ (also known as nitrile rubber).

(C) Polycarbonate is commonly used in the production of $LCD$ ($Liquid$ $Crystal$ $Display$) screens,primarily because it is a durable,transparent plastic with excellent optical properties. Polycarbonate is used to make the outer layers of the screen or protective covers due to its high impact resistance and clarity.
Here is a brief overview of the other options:
- $(A)$ Polyacrylamide: Used mainly in water treatment,paper production,and as a thickening agent; not typically used in $LCD$s.
- $(B)$ Buna-$N$: $A$ synthetic rubber (nitrile rubber) used for making seals,gaskets,and fuel hoses; not used in $LCD$s.
- $(D)$ Perspex: Also known as acrylic,it is a transparent plastic,but it is more commonly used in optical devices,displays,and lenses rather than $LCD$ screens.

(A) The copolymer formed by the condensation polymerization of $3$-hydroxybutanoic acid ($\beta$-hydroxybutyric acid) and $3$-hydroxypentanoic acid ($\beta$-hydroxyvaleric acid) is known as Poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate, abbreviated as $PHBV$.
The reaction is:
$n(HO-CH(CH_3)-CH_2-COOH) + n(HO-CH(CH_2CH_3)-CH_2-COOH)$ $\rightarrow [-O-CH(CH_3)-CH_2-CO-O-CH(CH_2CH_3)-CH_2-CO-]_n + 2nH_2O$
Thus, the correct option is $A$.

(A) The $-CO-NH-$ linkage is characteristic of amide groups,which are found in polyamides (like Nylon) and certain condensation polymers.
Urea formaldehyde resin is formed by the condensation reaction between urea and formaldehyde.
The structure of urea formaldehyde resin is: $[-NH-CO-NH-CH_2-]_n$.
This structure clearly contains the $-CO-NH-$ linkage.
Therefore,the correct option is $A$.

(A) $Glyptal$ is a polyester obtained by the condensation polymerization of glycerol and phthalic anhydride. It is widely used in the manufacture of paints and lacquers.

(A) Orlon,also known as polyacrylonitrile $(PAN)$,is a synthetic polymer that resembles wool and is used as a wool substitute. It is obtained by the polymerization of acrylonitrile monomer,which has the chemical formula $CH_2=CHCN$.

(D) Polyacrylonitrile $(PAN)$ is used as a substitute for wool in the form of acrylic fibers.
These synthetic fibers are often used to make fabrics that mimic wool,such as in clothing and blankets.

(A) Biodegradable polymers are those that can be decomposed by microorganisms.
Nylon $2$-nylon $6$ is a polyamide copolymer of glycine $(H_2N-CH_2-COOH)$ and amino caproic acid $(H_2N-(CH_2)_5-COOH)$.
It is a well-known biodegradable polymer used in medical sutures and other applications.
Other options like Terylene,Nylon $6$,and Nylon $6,6$ are synthetic polymers that are not biodegradable.

(A) In the process of vulcanization of rubber,accelerators are added to speed up the crosslinking process. $Zinc \ butyl \ xanthate$ is a commonly used accelerator for this purpose.

(A) Nylon $6$ (polyamide) possesses high tensile strength due to strong intermolecular hydrogen bonding,making it suitable for manufacturing tyre cords.

(D) Urea formaldehyde resin is a cross-linked polymer formed by the condensation reaction between urea and formaldehyde.
It is a classic example of a thermosetting polymer,which becomes hard and infusible upon heating.

(C) $HDPE$ (High Density Polyethylene) is a linear polymer with high density due to close packing. It is chemically inert and more tough and hard than $LDPE$. It is primarily used for manufacturing buckets,dustbins,bottles,pipes,and containers for storing chemicals and shampoos.

(A) Semisynthetic polymers,such as cellulose acetate,are used in the preparation of cinema films.

(A) $PHBV$ (Poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate) is a biodegradable aliphatic polyester.
It is obtained by the copolymerisation of $3-$hydroxybutanoic acid and $3-$hydroxypentanoic acid.
The reaction is:
$n CH_3-CH(OH)-CH_2-COOH n CH_3-CH_2-CH(OH)-CH_2-COOH \rightarrow -[O-CH(CH_3)-CH_2-CO-O-CH(CH_2CH_3)-CH_2-CO]_n-$

(A) Melamine is a thermosetting polymer formed by the condensation polymerization of melamine and formaldehyde.
Due to its high heat resistance and hardness,it is widely used in the manufacturing of unbreakable crockeries and kitchenware.

(C) Biodegradable polymers are those that can be decomposed by microorganisms.
$Dextron$ (also known as $PHBV$ or poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate) is a well-known biodegradable polymer.
$PVC$,$Polythene$,and $Teflon$ are synthetic,non-biodegradable polymers.

(A) Poly$(3-hydroxybutyrate-co-3-hydroxyvalerate)$ $(PHBV)$ is a biodegradable polymer.
It is obtained by the copolymerization of $3-hydroxybutanoic$ acid and $3-hydroxypentanoic$ acid.
$Buna-N$,$PTFE$,and $PVC$ are synthetic,non-biodegradable polymers.

(C) Nomex is a heat-resistant meta-aramid fiber. Due to its high thermal stability and flame resistance,it is widely used to manufacture protective clothing for firefighters.