Chemistry 9701 · AS & A Level · Polymerisation

Polymerisation — practice question

Compound W, $\text{CH}_2=\text{CHCN}$, is used in the production of an addition polymer that is found in carbon fibres.
(a)[1]

Draw a single repeat unit of the addition polymer formed from W.

(b(i))[1]

Name the mechanism for the reaction shown in step 1 in Fig. 6.1.

(b(ii))[3]

Complete Fig. 6.2 so that it shows the mechanism for the reaction in step 1. Add all products, charges, dipoles, lone pairs of electrons and curly arrows, where needed.

(b(iii))[1]

Suggest a suitable reagent and conditions for step 2 in Fig. 6.1.

(b(iv))[1]

Use Table 6.1 to work out which bonds are responsible for the absorptions marked S and T on Fig. 6.3.

(iv)[1]

Use Table 6.1 to work out which bonds cause the absorptions marked $S$ and $T$ on Fig. 6.3. $S$ .......................................... $T$ ..........................................

(c(i))[1]

Describe stereoisomerism.

(c(ii))[2]

Describe the two essential features of an alkene molecule that make geometrical stereoisomerism possible.

(d)[1]

Molecules of $\text{CH}_3\text{CH(OH)CN}$ occur as a pair of optical isomers. Draw three-dimensional diagrams in the boxes to show the optical isomers of $\text{CH}_3\text{CH(OH)CN}$.

(e)[1]

Propanenitrile is heated with hydrogen gas in the presence of a platinum catalyst, and propylamine is the only product. Construct an equation for this reaction.

(f(i))[1]

Propanenitrile can also be made in a two-step synthesis from propan-1-ol, as shown in Fig. 6.4. Name the type of reaction taking place in step 1 in Fig. 6.4.

(f(ii))[2]

Identify the reagent and the conditions for step 2 in Fig. 6.4.

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: accurate displayed formula of the cyanohydrin (either enantiomer acceptable)

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