Question

Consider the following polymerization reactions and the statements given about \(X\) and \(Y\). \[ \textbf{A.}\quad n\,\mathrm{C_6H_5CH=CH_2} \xrightarrow{\mathrm{RLi}} X \] \[ \textbf{B.}\quad n\,\mathrm{CH_2=CH-CH=CH_2} + n\,\mathrm{CH_2=CHCN} \xrightarrow{\mathrm{Peroxide}} Y \] \[ \begin{aligned} \textbf{I.}\quad & \text{The strength of intermolecular forces in } X>Y \\ \textbf{II.}\quad & X \text{ and } Y \text{ are synthetic rubbers} \\ \textbf{III.}\quad & X \text{ is a thermoplastic polymer and } Y \text{ is resistant to the action of petrol} \end{aligned} \] Correct statements are

• A. II, III only
• B. I, II only
• C. I, III only
• D. I, II, III \bigskip

Hint:

• Polystyrene \(\rightarrow\) Thermoplastic polymer.
• Buna-N \(\rightarrow\) Copolymer of butadiene and acrylonitrile.
• Buna-N is resistant to petrol, oils and organic solvents.

Answer 1

The Correct Option is C

Step 1: Identify the polymers. Reaction A is the anionic polymerization of styrene. \[ X=\text{Polystyrene} \] Reaction B is the copolymerization of buta-1,3-diene and acrylonitrile. \[ Y=\text{Buna-N (Nitrile rubber)} \]

Step 2: Analyse the statements.
• Statement I: Polystyrene has stronger intermolecular forces than Buna-N due to the presence of bulky phenyl groups. Hence, this statement is correct.
• Statement II: Polystyrene is a thermoplastic polymer, not a synthetic rubber, whereas Buna-N is a synthetic rubber. Hence, this statement is incorrect.
• Statement III: Polystyrene is thermoplastic and Buna-N is resistant to oils and petrol. Hence, this statement is correct.

Step 3: Final conclusion. Therefore, the correct statements are \[ \boxed{\text{I and III only}.} \] Hence, the correct option is \(\boxed{(C)}\).