Classification of Polymer Questions in English

(D) On the basis of the mode of their formation,polymers are classified into two types: addition polymers and condensation polymers.
Addition polymers are formed by the repeated addition of monomer molecules possessing double or triple bonds without the loss of any small molecules.
Condensation polymers are formed by the repeated condensation reaction between two different bi-functional or tri-functional monomeric units,usually involving the elimination of small molecules like $H_2O$,$CH_3OH$,etc.

(A) thermoplastic is a material,usually a plastic polymer,which becomes soft when heated and hard when cooled.
They possess linear or slightly branched molecular chains and lack significant cross-linking between the chains,which allows them to be reshaped upon heating.

(B) Shellac is a natural resin secreted by the female lac insect $(Laccifer \ lacca)$ on trees. It is a complex mixture of hydroxy fatty acids and is widely used as a natural polymer.

(D) Wax is a mixture of long-chain fatty acids and alcohols,which is a molecular solid and not a polymer.
Gun cotton is cellulose nitrate (a natural polymer derivative).
Perspex is polymethyl methacrylate (a synthetic polymer).
Shellac is a natural resinous polymer.

(D) Wool consists of protein,which is a polymer of amino acids.
Cotton is composed of cellulose,which is a naturally occurring polymer of glucose.
Leather is derived from animal skin,which is primarily composed of the protein collagen,a natural polymer.
Fat molecules are triglycerides,formed by the esterification of glycerol with three fatty acid molecules. They are not polymers because they do not consist of repeating structural units linked by covalent bonds in a long chain.

(A) Melamine-formaldehyde resin is a synthetic polymer formed by the condensation polymerization of melamine and formaldehyde.
It is a hard,durable,and heat-resistant material that does not soften upon heating.
Therefore,it is classified as a thermosetting plastic.

(A) $Cellulose$ is a natural polymer found in the cell walls of plants.
$PVC$,$Teflon$,and $Polyethylene$ are synthetic polymers.

(D) thermoplastic is a polymer that becomes pliable or moldable above a specific temperature and returns to a solid state upon cooling.
$Nylon$ is a thermoplastic material that can be melt-processed into fibers,films,or shapes.
$Polyethylene$ is a lightweight,durable thermoplastic with a variable crystalline structure.
$Terylene$ (also known as $Polyethylene \ terephthalate$) is a common thermoplastic polymer resin of the polyester family used in fibers for clothing and containers.
Since all the given compounds are thermoplastic polymers,the correct answer is $D$.

(C) . Starch is a natural polymer,whereas polyester,glyptal,and nylon $-6$ are synthetic polymers.

(D) Protein is a natural polymer of $\alpha$-amino acids.

(A) Low density polyethylene $(LDPE)$ has a highly branched structure due to free radical polymerization.
In contrast,high density polyethylene $(HDPE)$,polyester,and nylon are examples of linear polymers.

(B) An addition polymer is a polymer that forms by the simple linking of monomers without the co-generation of other products.
$Glucose$ is the monomer of polysaccharides like starch and cellulose.
$Polyethylene$ $(PE)$ is made by the reaction of multiple ethylene molecules in the presence of a catalyst to break the double bond and connect the carbon atoms into a chain without forming any by-products.
$Ethylene$ is the monomer of $polyethylene$.
$Terylene$ is a synthetic polyester fiber produced by polymerizing $ethylene \text{ } glycol$ and $terephthalic \text{ } acid$,which is obtained from petroleum with the removal of water. Hence,it is a condensation polymer. (Condensation polymers are formed through a condensation reaction,where molecules join together and lose small molecules as by-products such as water or methanol.)
Therefore,$Polyethylene$ is an addition polymer.

(D) Amylose is a linear polymer of $\alpha-D-Glucose$ units linked by $\alpha-(1 \rightarrow 4)$ glycosidic linkages.
Amylopectin,Glycogen,and Starch (which contains amylopectin) are branched polymers.

(D) The correct answer is $(d)$.
Silk is a natural protein fibre.
Dacron is a synthetic polyester fibre.
Nylon $-6,6$ is a synthetic polyamide fibre.
Therefore,all the given options are examples of fibres.

(B) Polyethylene is a homopolymer.
$n CH_2 = CH_2 \to -(CH_2 - CH_2)_n-$

(A) Cellulose is a natural polymer that is biodegradable.
Polythene,Polyvinyl chloride,and Nylon-$6$ are synthetic polymers,which are generally non-biodegradable.

(D) Condensation polymers are formed through a condensation reaction,where monomers join together and eliminate small molecules like $H_2O$ or $CH_3OH$ as by-products.
$1$. Polythene is formed by the addition polymerization of ethylene $(CH_2=CH_2)$ monomers.
$2$. $PVC$ (Polyvinyl chloride) is produced by the addition polymerization of vinyl chloride $(CH_2=CHCl)$ monomers.
$3$. Orlon (Polyacrylonitrile) is formed by the addition polymerization of acrylonitrile $(CH_2=CHCN)$ monomers.
$4$. Terylene (Dacron) is a condensation polymer formed by the polymerization of ethylene glycol $(HO-CH_2-CH_2-OH)$ and terephthalic acid $(C_6H_4(COOH)_2)$ with the elimination of water molecules.

(D) Nylon is a copolymer formed by the condensation of two different monomer units: hexamethylene diamine and adipic acid.
Since it is formed from two different monomers,it is classified as a copolymer,not a homopolymer.
$A$ homopolymer is formed by the polymerization of a single type of monomer unit.

(A) Terylene (or $Dacron$) is not an example of an addition polymer.
It is a condensation polymer formed by the reaction between ethylene glycol and terephthalic acid.
It is classified as a polyester.

(A) The simplest polymer architecture is a linear chain or a single backbone with no branches.
$A$ linear polymer is a long continuous chain of carbon-carbon bonds with the remaining two valence bonds attached primarily to hydrogen or another relatively small hydrocarbon moiety.
Among the given options,$Nylons$ are linear polymers,whereas $Bakelite$ and $Melamine-formaldehyde$ are cross-linked polymers,and $Low \ density \ polythene$ is a branched polymer.

(C) Natural rubber is $cis-1,4-polyisoprene$.
It is a linear polymer of isoprene.
Isoprene is $2-methyl-1,3-butadiene$.

(C) The polymer formed by condensation polymerization is known as a condensation polymer.
$Dacron$ (also known as $Terylene$) is a condensation polymer.
It is formed by the condensation polymerization of $terephthalic \ acid$ and $ethylene \ glycol$ with the elimination of water molecules.

(C) $PVC$ (Polyvinyl chloride) is a synthetic polymer prepared by the polymerization of vinyl chloride monomer. Cellulose,proteins,and nucleic acids are naturally occurring polymers found in plants and animals.

(B) The correct answer is $(b)$. There are $3$ stereochemical arrangements possible for a polymer of the type $-[CH_2-C(YZ)-]_n$:
$(i)$ Isotactic: Here,the groups are arranged on one side of the chain. All $Y$ groups lie on one side and all $Z$ groups lie on the opposite side of the chain.
$(ii)$ Syndiotactic: The $Y$ and $Z$ groups lie alternately on each side of the chain.
$(iii)$ Atactic: The $Y$ and $Z$ groups are arranged in a random fashion.

(C) Polymers of the type $Z-M_n-Y$,which contain a foreign molecule in addition to the recurring unit,are known as telomers.
The process of their formation is called telomerisation.

(B) $Perspex$ (poly(methyl methacrylate)) is a synthetic polymer,whereas rubber,protein,and cellulose are natural polymers.

(D) Polymers are macromolecules formed by the combination of a large number of repeating structural units.
Due to the presence of thousands of these repeating units,polymers possess a very high molecular mass,typically ranging from $10^3$ to $10^7 \ u$.

(B) Cross-linked polymers are formed by the presence of strong covalent bonds between various linear polymer chains. These bonds create a three-dimensional network structure,which makes the polymer hard,rigid,and infusible. Examples include Bakelite and melamine-formaldehyde resins.

(C) Molecular mass is a number equal to the sum of the atomic masses of the atoms in a molecule.
$A$ monomer is a molecule that forms the basic unit for polymers.
$A$ dimer is an oligomer consisting of two monomers joined by bonds that can be either strong or weak,covalent,or intermolecular.
$A$ polymer is a chemical compound with molecules bonded together in long,repeating chains.
An oligomer is a molecular complex of chemicals that consists of a few repeating units.
The polymer has the highest number of repeating units and hence,the maximum number of atoms,so it has the largest molecular mass.

(A) $CH_2=CH_2$ (ethylene) is a monomer.
Large number of ethylene monomeric units combine together through polymerization to form a polymer called polyethylene,as shown in the reaction: $n(CH_2=CH_2) \rightarrow -[CH_2-CH_2]_n-$.

(B) Natural rubber is a linear polymer of isoprene ($2$-methyl-$1,3$-butadiene).
Its monomer unit $X$ is isoprene,which has the chemical formula $CH_2=C(CH_3)-CH=CH_2$.

(B) Natural rubber is a linear polymer of $2$-methyl-$1,3$-butadiene,which is commonly known as $Isoprene$.
The polymerization reaction is:
$n CH_2 = C(CH_3) - CH = CH_2 \to -(CH_2 - C(CH_3) = CH - CH_2)_n$ (Natural rubber).

(D) $SO_2$,$CO_2$,and $CH_4$ are simple chemical compounds and exist in the gaseous state at room temperature.
$PVC$ (polyvinyl chloride) is a long-chain addition polymer formed from the polymerization of vinyl chloride monomers.

(A) thermoplastic,or thermosoftening plastic,is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.
This process of softening by heating and hardening by cooling can be repeated many times.
Thermosetting plastics,on the other hand,undergo extensive cross-linking during molding and cannot be remoulded or reused.

(D) Polymers are classified based on the magnitude of intermolecular forces present between the polymer chains.
$1$. Elastomers have weak intermolecular forces (e.g.,natural rubber).
$2$. Fibres possess strong intermolecular forces like hydrogen bonding or dipole-dipole interactions,which lead to close packing and crystalline nature (e.g.,polyamides like $Nylon-6,6$).
$3$. Thermoplastics and thermosetting polymers have intermediate to strong forces.
Among the given options,$Nylon-6,6$ (a polyamide) is a fibre that exhibits strong hydrogen bonding.

(B) Natural rubber is a linear polymer of $2$-methyl-$1,3$-butadiene,which is commonly known as isoprene. The polymerization reaction is represented as:
$n \, CH_2 = C(CH_3) - CH = CH_2 \to -[CH_2 - C(CH_3) = CH - CH_2]_n-$

(A) $CH_2 = CH_2$ (ethene) is the basic repeating unit used in the synthesis of polyethylene. Therefore,it is classified as a monomer.

(D) Natural polymers are those that occur naturally in plants and animals. Examples include proteins (like wool,silk,and leather),cellulose,starch,and natural rubber. $Nylon$ is a synthetic polymer,specifically a polyamide,which is manufactured in laboratories or industries. Therefore,$Nylon$ is not a natural polymer.

(NONE) homopolymer is a polymer formed from only one type of monomer unit.
Bakelite is a copolymer of phenol and formaldehyde.
Buna-$S$ is a copolymer of $1,3$-butadiene and styrene.
Dacron (Terylene) is a copolymer of ethylene glycol and terephthalic acid.
Butyl rubber is a copolymer of isobutylene and a small amount of isoprene.
However,in the context of standard chemistry questions,if we consider common polymers,none of the options provided are strictly homopolymers in their standard industrial forms. If the question implies a single monomer type,none fit perfectly. Re-evaluating: If the question intended to list a homopolymer like Polyethylene or $PVC$,but provided these,there might be an error. Given the options,none are homopolymers. However,if we must choose,often these questions are flawed. Assuming a correction is needed,if the question asked for a copolymer,all are correct. If it asks for a homopolymer,none are correct.

(B) Addition polymerization involves the repeated addition of monomers containing double or triple bonds without the loss of any small molecules.
Polystyrene,Polypropene,and $P.V.C$ (Polyvinyl chloride) are formed by the addition polymerization of styrene,propene,and vinyl chloride,respectively.
Nylon (e.g.,Nylon-$6,6$) is a condensation polymer formed by the reaction between hexamethylenediamine and adipic acid,which involves the elimination of small molecules like $H_2O$.

(C) Linear polymers consist of long and straight chains.
$PMMA$ (Polymethyl methacrylate) is a linear polymer.
Neoprene and Buna-$S$ are elastomers with cross-links or branched structures,and Glyptal is a thermosetting polymer with a highly cross-linked structure.

(A) Ice $(H_2O)$ is a molecular solid,not a polymer. Starch,protein,and cellulose are natural polymers.

(C) $DDT$ (Dichlorodiphenyltrichloroethane) is an organic compound used as an insecticide,but it is not a polymer. Silk,$DNA$,and starch are all naturally occurring polymers.

(B) Polymers are large molecules (macromolecules) formed by the repetition of structural units called monomers.
$A$. Teflon is a polymer of tetrafluoroethene.
$B$. Petroleum is a complex mixture of hydrocarbons,but it is not a polymer.
$C$. Cellulose is a natural polymer of glucose.
$D$. Natural rubber is a polymer of isoprene ($2$-methyl$-1,3-$butadiene).
Therefore,petroleum is not a polymer.

(A) Natural polymers are polymers that occur naturally in plants and animals. $Cellulose$ is a natural polymer found in plant cell walls. $PVC$,$Teflon$,and $Polyethylene$ are synthetic polymers.

(D) Neoprene is an addition polymer formed from the polymerization of chloroprene ($2$-chloro-$1,3$-butadiene).
Condensation polymers like Melamine,Glyptal,and Dacron are formed by the loss of small molecules like $H_2O$ or $HCl$ during polymerization.

(B) Polyethylene is formed by the polymerization of a single type of monomer unit,which is ethene $(CH_2=CH_2)$.
Since it consists of only one type of repeating unit,it is classified as a homopolymer.

(A) copolymer is a polymer formed from two or more different types of monomer units.
Buna-$S$ is a copolymer formed by the polymerization of $1,3$-butadiene and styrene.
Teflon,$PVC$,and Polypropylene are homopolymers,as they are formed from a single type of monomer unit (tetrafluoroethene,vinyl chloride,and propene,respectively).
Therefore,the correct answer is Buna-$S$.

(D) Silk is a protein-based natural fiber.
Dacron is a polyester fiber.
Nylon-$66$ is a polyamide fiber.
Therefore,all of the given options are examples of fibers.

(D) Polymers are classified based on the mode of polymerization into two main types:
$1$. Addition polymers: Formed by the repeated addition of monomer molecules possessing double or triple bonds.
$2$. Condensation polymers: Formed by repeated condensation reactions between two different bi-functional or tri-functional monomeric units,often involving the loss of small molecules like $H_2O$,$HCl$,or $NH_3$.
Therefore,the correct classification includes both addition and condensation polymers.