Polymers

• A. Electrodes in batteries:

  • Polyacetylene (II) is a conductive polymer that, when doped, can achieve electrical conductivities similar to metals. This property makes it suitable for use as an electrode material in some types of batteries, particularly in the early development of conducting polymer batteries.

  • Polypropylene (I) is used for battery cases, not electrodes.

  • Oxyacetylene (III) is a gas mixture for welding.

  • Therefore, A matches II.

• B. Welding of metals:

  • Oxyacetylene (III) is a mixture of oxygen and acetylene gas, which when ignited, produces a very hot flame (up to 3200°C). This high-temperature flame is widely used for welding, cutting, and heating metals.

  • Polypropylene (I) and Polyacetylene (II) are polymers and not directly used for welding metals in this context.

  • Therefore, B matches III.

• C. Toys:

  • Polypropylene (I) is a versatile thermoplastic polymer known for its durability, flexibility, chemical resistance, and relatively low cost. It is widely used in the manufacturing of various plastic products, including many types of toys.

  • Polyacetylene (II) is a specialized conductive polymer, not typically used for common toys.

  • Oxyacetylene (III) is a gas mixture, not a material for toys.

  • Therefore, C matches I.

Combining these matches:

A - II

B - III

C - I

Step 1: Find the total mass for each type of molecule

There are 10 molecules, each with a mass of 5,000. So, the total mass for these is:

$ 10 \times 5000 = 50000 $

There are 5 molecules, each with a mass of 50,000. So, the total mass for these is:

$ 5 \times 50000 = 250000 $

Step 2: Add total masses and total number of molecules

Add the total masses together:

$ 50000 + 250000 = 300000 $

Add the total numbers of molecules:

$ 10 + 5 = 15 $

Step 3: Calculate the number average molecular mass

Use the formula:

$ \mathrm{M}_n = \frac{\sum n_i M_i}{\sum n_i} = \frac{300000}{15} = 20000 $

There are three linear polymer

Nylon-6,6 PVC, Novolac

Linear polymers have a chain like structure with monomer linked in single line

There are two cross linked polymer.

Melamine, Bakelite

$ \text { It is a biodegradable polymer. } $

Both statement I and statement II are incorrect. This correct forms are Nylon 6 is a condensation homopolymer, Nylon 6,6 is made from adipic acid and hexamethylene diamine.

$ \text { The complete polymerisation reaction is, } $

$ \text { Thermoplastic polymer (Product } Y \text { ). } $

The incorrect statement about silicon is

It has low dielectric strength.

The correct form is, it has high dielectric strength and due to this it is good insulator.

The correct match is, A-II, B-IV, C- I, D-III

$ \text { Complete reaction is, } $

$ \text { Free radical polymerisation } $

$ \text { (Ziegler - Natta polymerisation) } $

$ \text { The complete polymerisation is, } $

The common monomer for bakelite and melamine is formaldehyde

$ \text { Phenol-formaldehyde resin } $

$ \text { Melamine-formaldehyde resin. } $

High density polythene is prepared using Ziegler-Natta catalyst. Ziegler - Natta catalyst: A transition metal halides + Organoaluminium compound e.g. $\mathrm{TiCl}_4+\mathrm{Al}\left(\mathrm{C}_2 \mathrm{H}_5\right)_3$

The correct answer is Option D: thermoplastic polymers.

Here's why:

Thermoplastic polymers soften when heated and harden again upon cooling. This property allows them to be remolded repeatedly.

In contrast, thermosetting polymers (such as bakelite) undergo a curing process that permanently locks their structure, so they do not soften upon reheating.

Fibres refer to materials with long, flexible strands and are not classified based on heat-softening properties.

Thus, polymers that can be softened on heating and hardened on cooling are called $\textbf{thermoplastic polymers.}$

Statement given in option (b) is correct, while all other are incorrect.

The correct statements are:

(a) Starch is a polymer of $\alpha-\mathrm{D}$ glucose.

(c) Proteins are made of up to 20 different amino acids, so protein is heteropolymers or copolymers.

(d) Lactose is a disaccharide of $\beta-\mathrm{D}$ glucose and $\beta$-D-galactose.

Set given in option (a) is not

The correct match is A-III, B-I, C-IV, D-II.

A. Elastomer are any rubber material composed of long chain like polymers that are capable of recovering to original shape after stretching $\longrightarrow$ Buna-N Rubber is elastomer. (Inter-particle force is weakest : van der Waals' force)

B. Fiber forming polymers are linear macromolecules that are suitable for synthetic fiber $\longrightarrow$ Terylene is synthetic fiber.

(Inter-particle force is strongest : H-bonding)

C. A thermoplastic polymer are those polymer that can softern on heating and then processed. Polystyrene is an example.

D. Thermosetting polymers are semifluid substance with low molecular mass, when heated in mould undergo a permanent change, in composition. Urea-formaldehyde resin is an example.

Option A: Polystyrene is formed by the polymerization of styrene and is a homopolymer (made from a single type of monomer), not a copolymer. Although it is a thermoplastic, the first part of the match is incorrect.

Option B: Bakelite is a thermosetting resin, but it is produced via a condensation reaction (not addition), so calling it an "addition polymer" is incorrect.

Option C: Nylon 6 is produced from caprolactam by ring-opening polymerization, making it a homopolymer. It is widely used in the textile industry as a fiber.

$\text{Nylon 6 (a homopolymer of caprolactam) → Fiber}$

This option is correctly matched.

Option D: Buna-N, also known as nitrile rubber, is a copolymer (usually made from butadiene and acrylonitrile), not a homopolymer, although it is an elastomer.

Thus, the correctly matched set is:

Option C: Nylon 6 – homopolymer – fiber.

Ethylene glycol is the common monomer for both terylene and glyptal.

Ethylene glycol

Chloroprene is the monomer of neoprene. The complete reaction is as follow.

Among the given, polyethylene terephthalate is a fibre polymer (a polyester).

Its monomers are ethylene glycol and terephthalic acid.

PHBV (IUPAC name) 3-hydroxybutyrate-CO- 3 hydroxy valerate) is a polyhydroxy alkanoate type polymer. The monomers are

(i) 3 hydroxybutyrate ( 3 HB )

$ X=\mathrm{CH}_3-\mathrm{CH}(\mathrm{OH})-\mathrm{CH}_2 \mathrm{CO}_2 \mathrm{H} $

(ii) 3 hydroxyvalerate ( 3 HV )

$ Y=\mathrm{C}_2 \mathrm{H}_5 \mathrm{CH}(\mathrm{OH}) \mathrm{CH}_2 \mathrm{CO}_2 \mathrm{H} $

Among the given options monomer given in option (d) will give biodegradable polymer i.e., PHBV.

Preparation of polyethylene is done in the presence of the "Zeigler-Natta catalyst" which is a mixture of trimethylaluminium $\left[\mathrm{Al}\left(\mathrm{CH}_3\right)_3\right]$ and titanium tetrachloride $\left(\mathrm{TiCl}_4\right)$.