Polymers practice · Easy

Option D (Thermosetting) is correct because Bakelite is a thermosetting polymer.

Option C ($\mathrm{C}{\mathrm{H}_2} = \mathrm{CH}{\mathrm{C}_6}{\mathrm{H}_5}$) is correct because styrene forms a more stable carbocation intermediate due to resonance stabilization by the phenyl group, facilitating chain growth polymerization.

Option A (Rayon) is correct because rayon is known for its high water absorption capacity and non-sticking properties, making it suitable for wound dressings.

Option C ($50^{\circ}$ to $80^{\circ} \mathrm{C}$) is correct because the Ziegler process for polythene manufacture typically uses a temperature range of $50^{\circ}$ to $80^{\circ} \mathrm{C}$.

Option C (Semi-synthetic) is correct because cellulose diacetate fiber is derived from a natural polymer (cellulose) through chemical modification.

Option C (2, 4, 6-triamino-1, 3, 5-triazine) is correct because that is the correct IUPAC name for the melamine molecule.

Option C (Bakelite) is correct because it is a thermosetting polymer that hardens irreversibly upon heating.

Option B (Liquid) is correct because styrene is a liquid at room temperature.

The correct answer is $4,3,2,1$ because as the number of carbon atoms between the amide groups increases, the amide density decreases, leading to a lower melting point.

The correct answer is D (Terylene) because Terylene is a thermoplastic polymer, not a thermosetting plastic.

Option B (Both A and R are correct, but R is not the correct explanation of A) is correct because both the assertion and the reason are true statements, but the reason does not explain the assertion.

Option C (Condensation polymer) is correct because bakelite is formed through a condensation reaction between formaldehyde and phenol, with the elimination of water.

Option B (Nylon-6,6) is correct because Nylon-6,6 is formed by the condensation polymerization of hexamethylene diamine and adipic acid.

Option C (SBR is called natural rubber) is wrong because SBR (Styrene-Butadiene Rubber) is a synthetic rubber, while natural rubber is polyisoprene.

Option B is correct. Assertion is correct as the empirical formula of natural rubber is ${C}_5 {H}_8$. Reason is also correct as natural rubber contains no conjugative double bonds, but it's not the explanation for the empirical formula.

Option B (Isoprene) is correct because natural rubber is a polymer made up of isoprene units.

Option A (Thermoplastics) is correct because thermoplastics can be repeatedly softened by heating and hardened by cooling, allowing for repeated molding.

Option B (Terylene) is correct because Terylene (also known as Dacron) is a polyester polymer formed from ethylene glycol and dimethyl terephthalate.

Option C (Glycerol) is correct because glycerol can be nitrated to form glycerol trinitrate, also known as nitroglycerin, which is a powerful explosive.

Option D (Ethylene glycol and terephthalic acid) is correct because terylene (Dacron) is a polymer formed from the monomers ethylene glycol and terephthalic acid.

Option B ($cis$-isoprene) is correct because natural rubber is a polymer formed from the repeated units of cis-isoprene (2-methyl-1,3-butadiene).

Option B (Novalac) is correct because Novalac is a linear polymer formed by the reaction of phenol and formaldehyde, while Bakelite is a cross-linked polymer.

Option B (Low density polythene) is correct because low-density polyethylene (LDPE) is produced through a free-radical polymerization process that results in significant chain branching.

Option B ($\left({C}_2 {H}_5\right)_3 {Al}+{TiCl}_4$) is correct because Ziegler-Natta catalysts are typically composed of a transition metal halide (like TiCl4) and an organometallic compound (like triethylaluminum).

Option C (Adipic acid and hexamethylenediamine) is correct because nylon-66 is a polyamide formed by the condensation polymerization of adipic acid and hexamethylenediamine.

Option D (Glyptal) is correct because Glyptal is a step-growth polymer, not a chain-growth polymer.

Option D (Bakelite) is correct because Bakelite is a thermosetting polymer formed from the condensation reaction of formaldehyde and phenol.

Option A (Rubber) is correct because rubber is a natural polymer, while Nylon-6, Nylon-6,6, and Nylon-6,10 are synthetic fibers.

The correct answer is D (Alkyd resin) because glyptal is a type of alkyd resin formed by the polymerization of phthalic acid and glycerol.

Option C (Regenerated fibre) is correct because rayon is made from cellulose that has been chemically processed and reformed.