(a) A series of reactions starting from 1-bromobutane is shown. [Figure showing reaction scheme: 1-bromobutane reacts with HCN and KCN to form P, then P undergoes reaction 1 to form CH₃(CH₂)₃CO₂H; 1-bromobutane reacts with OH⁻(aq) to form R, then R undergoes reaction 2 to form but-1-ene; but-1-ene forms polymer Q]

1. (a)(i)Draw the displayed formula of compound P.[1]
2. (a)(ii)Identify the reagent(s) and conditions for reactions 1 and 2. reaction 1 reaction 2[2]
3. (a)(iii)Draw the structure of the repeat unit of polymer Q.[2]
4. (b)Complete the reaction scheme to show the mechanism of the reaction of 1-bromobutane with OH⁻(aq) to produce R. Include all necessary charges, dipoles, lone pairs and curly arrows and the structure of R. [Partial diagram showing CH₃CH₂CH₂-C(H₂)-Br and -OH reactant][3]
5. (c)(i)But-1-ene reacts with steam as shown to form a mixture of two structural isomers, S and T. [Figure showing reaction scheme: but-1-ene + steam → S (major product) + T (minor product); S + reflux Cr₂O₇²⁻/H⁺ → U] S can be oxidised with acidified potassium dichromate(VI) to form compound U. S and U both react with alkaline aqueous iodine. Identify the type of reaction that occurs when but-1-ene reacts with steam.[1]
6. (c)(ii)State what can be deduced about the structure of S from its reaction with alkaline aqueous iodine.[1]
7. (c)(iii)Explain why S is the major product of the reaction of but-1-ene with steam.[2]
8. (c)(iv)Draw the skeletal formulae of S, T and U.[3]
9. (c)(v)Write an equation to represent the oxidation of S to U by acidified potassium dichromate(VI). You should use [O] to represent the oxidising agent.[1]
10. (d)(i)CH₃(CH₂)₂CO₂H is a colourless liquid with an unpleasant odour. It reacts with methanol in the presence of an acid catalyst to produce an organic product V, which has a pleasant fruity smell. Name V.[1]
11. (d)(ii)A student analysed CH₃(CH₂)₂CO₂H, methanol and V using infra-red spectroscopy. The spectra were returned to the student without labels. Identify which of the infra-red spectra, X, Y or Z, corresponds to V. compound | CH₃(CH₂)₂CO₂H | methanol | V ---|---|---|--- spectrum | | | Explain your answer with reference to relevant features of the three spectra in the region above 1500 cm⁻¹. [Figure showing infra-red spectrum X, Y, Z on page 15][4]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.