Question

what monomer is used to form the polymer below? image of polymer and monomer options none of the answers represent the monomer subunit used.

Explanation:

Step1: Recall Polymerization (Addition)

Polymers formed by addition polymerization come from alkenes (monomers with \( C = C \)) where the double bond breaks to form single bonds in the polymer chain.

Step2: Analyze Polymer Structure

The polymer has repeating units with \( \text{CH}_3 \), \( \text{Cl} \), \( \text{Br} \), \( \text{CN} \) attached to carbon atoms in a chain (single bonds between C atoms). So the monomer should be an alkene (has \( C = C \)) with the same substituents as the polymer's repeating unit.

Step3: Match Substituents to Monomer

Looking at the polymer's repeating unit (each pair of C atoms in polymer was a \( C = C \) in monomer), the substituents on each C of the monomer's \( C = C \) should match. The third option (monomer with \( \text{CH}_3 \), \( \text{Cl} \) on one C; \( \text{Br} \), \( \text{CN} \) on the other C, and \( C = C \)) has the correct substituents that, when the double bond breaks, form the polymer's single - bonded chain with those groups attached. The first two options are alkanes (single bonds between C), so they can't form the polymer via addition (needs double bond to break). The fourth option has different substituent placement.

Answer:

The third option (the monomer with \( \text{CH}_3 \), \( \text{Cl} \) on one \( C \), \( \text{Br} \), \( \text{CN} \) on the other \( C \), and a \( C = C \) double bond)