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Correct option is (a) True

Best explanation: It is a POLYAMIDE copolymer of an AMINO acid NH2-CH2-COOH (GLYCINE) and NH2-(CH2)5-COOH (amino caproic acid). The two monomer units alternate after each other. It is an important biodegradable copolymer.

The correct OPTION is (c) Teflon

To elaborate: Teflon (polymer of TETRAFLUOROETHENE) is CHEMICALLY inert and resistant to attacks by corrosive agents. This makes it suitable for use in making oil seals, gaskets and also in non-stick surface COATED UTENSILS.

Correct answer is (b) Mw/Mn

The explanation: Polydispersity index (PDI) is defines as the ratio of weight average MOLECULAR MASS to the number average molecular mass. It GIVES an idea of the homogeneity of the polymer.

The correct answer is (d) Triethylaluminium-titanium tetrachloride

Easy explanation: Dacron or terylene is a polyester of ethylene glycol and terephthalic acid. It is PRODUCED by HEATING the TWO at 420-460K and in the presence of zinc acetate-antimony trioxide, which acts as a catalyst. On the other HAND, triethylaluminium-tetrachloride is used in the synthesis of HDPE.

The correct answer is (b) False

The BEST explanation: TERYLENE, also known as polyethylene terephthalate, is a thermoplastic polymer of the polyester family. Terylene is MADE from the condensation polymerisation of terephthalic acid and ethylene glycol.

Correct CHOICE is (c) PVC

Explanation: Elastomers are polymers that have rubber like elastic properties. The polymer chains are held TOGETHER by the WEAKEST intermolecular forces, which facilitate the stretching of the polymer. PVC is a plastic and not an ELASTOMER.

Right answer is (b) o-Hydroxybenzyl alcohol and p-hydroxybenzyl alcohol

To elaborate: NOVOLAC is a linear chain PHENOL-formaldehyde polymer. The ortho and para hydroxy derivatives of benzyl alcohol, initially formed by the reaction of phenol with HCHO, further react with phenol to FORM COMPOUNDS having benzene rings joined together by -CH2– links (Novolac).

Right OPTION is (d) 3-Hydroxybutanoic ACID, 3-hydroxypentanoic acid

Easy EXPLANATION: PHBV is SHORT for poly β-hydroxybutyrate-co-β-hydroxy valerate. This shows that is a copolymer of β-hydroxybutyrate (3-hydroxybutanoic acid) and β-hydroxy valerate (3-hydroxypentanoic acid). PHBV is BIODEGRADABLE as it can be decomposed by bacteria.

Right answer is (d) Polylactic acid

For explanation I would say: Polylactic acid (PLA) is ONE of the most common BIOPLASTICS which can be EASILY BROKEN down by SOIL microorganisms and does not cause any negative effects on the environment. It is a polyester made from lactic acid and lactide.

Right answer is (b) Isoprene

For explanation: Isoprene (or 2-methyl-1,3-butadiene) repeats itself in a linear chain to form natural rubber. This is also called as cis-1,4-polyisoprene, in which the monomers are linked by WEAK van der Waals FORCES, THUS making it elastic in NATURE.

Correct answer is (c) LDPE

Explanation: LOW DENSITY polyethylene is a plastic that cannot be decomposed by the abiotic SOURCES and MICROORGANISMS and have a harmful effect on the environment.

The CORRECT CHOICE is (b) BLOCK

Best explanation: BOCK copolymers are those in which blocks of each type of monomer alternate with each other. In this case, the block AAAA and block BBB are alternatively repeated after each other.

Right option is (a) Nylon

For EXPLANATION I WOULD say: FIBRES are polymers which have strong intermolecular forces between the chains, either by hydrogen bonding or dipole-dipole interactions. In case of polyamides (nylon), the forces are hydrogen bonding, WHEREAS in polyesters (terylene, DACRON) and polyacrylonitriles (orlon) it is dipole-dipole interactions.

Correct choice is (a) Ethane

Explanation: The MONOMERS involved in ADDITION polymerisation are unsaturated compounds like alkenes and alkadienes. This is because it does not involve the REMOVAL of any molecule and hence requires the breaking of a DOUBLE bond for it to progress.

Right ANSWER is (a) Rayon

Easy EXPLANATION: The POLYMERS obtained from plants and animals are called natural polymers. Rayon is a semi-synthetic polymer which is derived from a natural polymer by chemical modification. CELLULOSE on acetylation with acetic anhydride in sulphuric ACID gives cellulose acetate polymer or rayon.

The correct answer is (d) Bakelite

The explanation: Bakelite is a cross-linked THERMOSETTING polymer, which on HEATING UNDERGOES extensive cross-linking and undergo permanent change. They cannot be reused.

Right choice is (b) 2-Chloro-1,3-butadiene

To explain: Neoprene or polyisoprene is a synthetic rubber OBTAINED from the addition polymerisation of chloroprene (2-chloro-1,3-butadiene) through free RADICAL MECHANISM. It has a BETTER stability towards OXIDATION than natural rubber.

Right answer is (a) Nylon-6

The explanation is: Nylon-6 is the polymer of caprolactam (Q), which is obtained from the OXIDATION of cyclohexane to GIVE cyclohexanone(P), followed by treatment with H2SO4. Caprolactam on heating with water GIVES amino caproic acid which polymerises to nylon-6.

The correct answer is (d) Benzoquinone

The explanation: Benzoquinone combines with the FREE radical intermediate to form a highly STABLE, non-reactive radical because of resonance. This inhibits the further progress of the CHAIN growth and therefore, the reaction stops. Peroxides are very important free radical generating INITIATORS.

Correct option is (a) Low-density polythene

Explanation: The shown structure has unconnected linear chains with some INTERMEDIATE BRANCHES. This is a BRANCHED chain polymer. They are IRREGULARLY packed and have lower density and strength than linear POLYMERS.

Right option is (B) False

Explanation: Polymers consists of thousands of repeating units, and are macromolecules because of their very large size and high MOLECULAR mass (10^3 to 10^7 u). However, a macromolecule may or may not CONTAIN repeating monomer units (for EXAMPLE, chlorophyll). THEREFORE, all polymers are macromolecules, but all macromolecules are not polymers.

Right option is (b) Nomex

For explanation: Nomex is a highly fire-resistant meta-aramid POLYMER that is rigid and durable. Its monomers are m-phenylenediamine and isophthaloyl CHLORIDE. It is COMMONLY used in firefighting EQUIPMENT and in the driving apparel of racers to PROTECT them in the case of a fire.

The CORRECT choice is (a) True

For explanation: Phenol-formaldehyde condensation initially forms a linear polymer, Novolac. This on further HEATING with formaldehyde UNDERGOES cross-linking through CH2 groups to form bakelite.

Right choice is (B) PAN

The best I can EXPLAIN: POLYACRYLONITRILE (PAN) is a polymerised PRODUCT of acrylonitrile (vinyl cyanide) in the presence of a peroxide catalyst. Vinyl cyanide can be prepared by treating ETHYNE with HCN in the presence of Ba(CN)2 catalyst. PAN is used for making orlon and acrilan.

Right ANSWER is (a) C6H5• + C2H4 = C6H5-CH2-CH2•

To elaborate: BENZOYL peroxide undergoes homolytic fission to from phenyl free radical which ACTS an initiator. The first step is the ADDITION of this radical to the ethene double bond, thus GENERATING a new and larger free radical. This is called the chain initiating step.

Correct choice is (B) Temperature of 500K

To elaborate: HDP is formed when polymerisation of C2H4 takes place through addition in a hydrocarbon SOLVENT with Ziegler-Natta CATALYST at temperature of 333-343K and under a pressure of 6-7 atmospheres. Temperatures and pressure higher than this will FAVOUR the formation of LDP.

Correct choice is (d) Both are CHEMICALLY inert

To explain I would say: Low-density and high-density polythene have the same MONOMERIC unit, ETHENE. Both are SYNTHESIZED under very different pressure and temperatures conditions. LDP has a branches whereas HDP is a linear structure. Both are chemically inert and tough.

Right choice is (B) Polycondensation polymerisation

The explanation: Depending on the nature of the reactive SPECIES involved, addition polymerisation is classified as free radical, ANIONIC and cationic based on whether the initiator is a free radical, anion or CATION respectively.

The correct ANSWER is (a) Buna-N

The best I can explain: Elastomers (buna-N) have the weakest INTERMOLECULAR forces WHEREAS fibres (nylon-6,6) have very strong intermolecular forces due to hydrogen bonds and dipole-dipole forces. THERMOPLASTIC polymers (polythene, POLYSTYRENE) have intermolecular attractions intermediate to that of elastomers and fibres.

Right option is (c) RESISTANT to attack by OXIDISING agents

The best I can explain: Natural rubber BECOMES soft at temperatures above 335K and SHOWS brittle character at temperatures below 283K. Hence, it shows THERMOPLASTIC behaviour. It is soluble in non-polar solvents like benzene, toluene, etc. and is not susceptible to attack by oxidising agents.

The correct OPTION is (b) phthalic acid

To explain: GLYPTAL is a POLYESTER (containing COO linkages) obtained from the polycondensation reaction of ethane-1,2-diol and benzene-1,2-dicarboxylic acid (phthalic acid). It is cross-linked polymer.

Right choice is (C) 1

Easy EXPLANATION: Natural polymers generally have chains of identical lengths and have definite molecular masses (Mw=Mn). This makes them more HOMOGENEOUS and monodisperse, with a PDI of approximately 1.

The correct answer is (b) False

Easy explanation: TERYLENE is a polycondensation PRODUCT of a dicarboxylic acid (terephthalic acid) and a DIOL (ethylene glycol) involving ESTER (COO) linkages. Hence, it is a polyester.

Correct option is (a) True

Explanation: LDP is chemically inert and TOUGH but flexible and a POOR conductor of electricity. This makes it SUITABLE for use in the INSULATION of electricity carrying wires.

Correct ANSWER is (c) Elastomers

Best explanation: On the basis of source, polymers are CLASSIFIED as natural, semi-SYNTHETIC or synthetic. Elastomers are a CLASS of polymers based on the molecular forces.

The correct option is (d) CHAIN growth polymerisation

Explanation: ADDITION polymerisation takes place through steps leading to the increase in chain length and each step PRODUCES REACTIVE intermediates for use in the next STAGE of the growth of the chain. It may take place between molecules of the same monomer or different monomers.

Correct option is (b) NUMBER of monomers

For explanation: Polymers are very LARGE molecules formed by joining together huge number of simple units, or monomers. They are mainly CLASSIFIED on the BASIS of their source, STRUCTURE, mode of synthesis and molecular forces.

Correct CHOICE is (c) GLYPTAL

Explanation: Glyptal is a copolymer of ethylene glycol and phthalic acid. It is an important COMPONENT in the manufacturing of PAINTS, lacquers and BUILDING materials.

The correct answer is (B) False

Best explanation: The weighted AVERAGE molecular mass is always greater than the NUMBER average molecular mass. This is because of the 2-degree nature of Mw (because of squaring of MASSES). Hence PDI ≥ 1.

Correct option is (c) Persulphate

Easiest explanation: This is the addition polymerisation of tetrafluoroethene to GIVE Teflon. It is CARRIED out in the presence of a FREE radical or persulphate catalyst at high pressures.

Correct choice is (C) Dipole-dipole interaction between CARBONYL and cyano GROUPS

The best I can explain: Acrilan is a fibre of polyacrylonitrile. It FORMS strong intermolecular bonds through dipole-dipole INTERACTIONS between the carbonyl and cyano groups.

Correct OPTION is (c) VECTRAN

To explain I would say: PMMA is a POLYMER of methyl methacrylate. It is used in the manufacturing of lenses, dentures, aircrafts windows, ETC. It is known by the commercial names PLEXIGLASS, lucite, acrylite, perspex and crylux. Vectran is an aromatic polyester.

Correct answer is (C) 26250

The best explanation: Since the 4 MONOMERS are present in equal amount, there is 25% of each monomer in the polymer. The NUMBER average molecular mass is,

\(\Rightarrow\) Mn = (25×10000 + 25×15000 + 25×30000 + 25×50000)/(25+25+25+25)

\(\Rightarrow\) Mn = (250000+375000+750000+1250000)/100

\(\Rightarrow\) Mn = 2625000/100

\(\Rightarrow\) Mn = 26250.