Chemistry 9701 · AS & A Level · Polymerisation

Polymerisation — practice question

Polyvinyl acetate, PVA, works well as an adhesive for joining objects made from wood, paper or cardboard. Its monomer is ethenyl ethanoate, B, and PVA is produced from B by addition polymerisation.
(a(i))[2]

Show a portion of the PVA molecule containing at least 2 monomer molecules, and make the repeat unit easy to recognise.

(a(ii))[2]

Use the information given to predict a possible structure for C and place it in the box above. Ester B can be hydrolysed in the normal way, as shown by the equation: B + H$_2$O $\rightarrow$ CH$_3COOH$ + C (C$_2$H$_4$O).

(a(iii))[1]

After C is isolated from the product mixture, it is observed that it does not decolourise Br$_2$(aq), yet it does give a pale yellow precipitate with alkaline aqueous iodine. Propose a structure for C that is consistent with this evidence.

(a(iv))[1]

Suggest a confirmatory test for the functional group in the structure you have drawn in (iii). Your response should give both the reagent used and the observation expected.

(b(i))[1]

In the formula above, add brackets [ ] around the atoms that form the polymer repeat unit.

(b(ii))[1]

Name the functional group present in polymer D.

(b(iii))[1]

Suggest and draw the structure of the monomer, E, that could produce this polymer.

(b(iv))[1]

What type of polymerisation is used to make polymer D from its monomer?

(b(v))[1]

What is the relationship between the repeat unit of polymer D and the repeat unit of PVA?

(c(i))[1]

Name the type of stereoisomerism exhibited by compound E.

(c(ii))[3]

Suggest structures for F and G, and name the type of stereoisomerism they show.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: Displayed / structural / skeletal formula of the repeat unit is correct

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