WAEC 2011 Chemistry · Question 42

The following substances are examples of addition polymer except

Options

A.nylon
B.perspex
C.polyethene
D.polychloroethene

Answer: A. nylon

Explanation written with AI and checked against the answer key

Analyze the question: We need the one substance that is NOT an addition polymer.

Concept:

Addition polymers form when unsaturated monomers (containing C=C double bonds) join together with no loss of any small molecule. Examples: polyethene, PVC, perspex, polystyrene.
Condensation polymers form when monomers join with the loss of a small molecule, usually water or HCl. Examples: nylon, terylene (polyester), proteins, starch.

Check each option:

A. Nylon: Made from a diamine and a dicarboxylic acid (or diacid chloride), with water (or HCl) eliminated, forming amide (peptide) linkages. This is a condensation polymer.
B. Perspex: Poly(methyl methacrylate), made from methyl methacrylate monomers that contain C=C. This is an addition polymer.
C. Polyethene: Made from ethene, CH₂=CH₂. This is an addition polymer.
D. Polychloroethene (PVC): Made from chloroethene, CH₂=CHCl. This is an addition polymer.

Answer: Nylon is the odd one out, since it is a condensation polymer. So by my working the correct option is **B?

Tip: Remember "Nylon and Terylene are Condensation." Polymers with names starting with "poly" plus an alkene name (polyethene, polypropene, polystyrene, polychloroethene) are usually addition polymers. Nylon contains the amide link -CONH-, which is a sign of condensation.

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