In polymer chemistry, identify the correct monomer used to synthesize poly(vinyl chloride) (PVC) via chain-growth polymerization from vinyl monomers.

Introduction / Context:
PVC (poly(vinyl chloride)) is one of the world’s most widely used thermoplastics. The question tests understanding of monomer–polymer relationships and basic nomenclature in polymer science, which is fundamental for materials selection and processing in chemical engineering and plastics manufacturing.

Given Data / Assumptions:

• PVC is formed by addition (chain-growth) polymerization.
• Possible precursors include several chlorinated C1–C2 molecules listed in the options.
• Nomenclature: chloroethene is the systematic name for vinyl chloride.

Concept / Approach:
In chain-growth polymerization, unsaturated monomers containing carbon–carbon double bonds (like alkenes) add to a growing radical, cation, or anion. PVC specifically arises from polymerization of vinyl chloride, whose IUPAC name is chloroethene (CH2=CH–Cl). Molecules lacking a double bond or being too small/incorrectly substituted cannot serve as the direct monomer for PVC under standard processes.

Step-by-Step Solution:

Verification / Alternative check:
Industrial PVC is produced by bulk, suspension, or emulsion polymerization of vinyl chloride monomer (VCM). The reaction yields –CH2–CH(Cl)– repeating units, matching PVC’s structure.

Why Other Options Are Wrong:

• Ethylene dichloride: A saturated dihalide; used to manufacture VCM via cracking, but not itself the polymerization monomer for PVC.
• Chloroform: Trihalomethane with no C=C; cannot undergo vinyl addition.
• Ethyl chloride: Saturated alkyl chloride; no double bond.

Common Pitfalls:
Confusing feedstock or intermediates (like ethylene dichloride) with the actual monomer. Only the vinyl chloride (chloroethene) molecule polymerizes directly to PVC.

Final Answer:
chloroethene