Chemistry 9701 · AS & A Level · Organic synthesis

Organic synthesis — practice question

A sequence of reactions beginning with 1-bromobutane is shown.
(a(i))[1]

Draw the displayed formula for compound P.

(a(ii))[2]

Identify the reagent(s) and conditions for reactions 1 and 2.

(a(iii))[2]

Draw the structure of the repeat unit of polymer Q.

(b)[3]

Complete the reaction scheme to show the mechanism for the reaction between 1-bromobutane and $\text{OH}^-(aq)$ that forms R. Include every necessary charge, dipole, lone pair and curly arrow, together with the structure of R.

(c(i))[1]

Identify the type of reaction that occurs when but-1-ene reacts with steam.

(c(ii))[1]

State what can be deduced about the structure of S from its reaction with alkaline aqueous iodine.

(c(iii))[2]

Explain why S is the major product of the reaction of but-1-ene with steam.

(c(iv))[3]

Draw the skeletal formulae of S, T and U.

(c(v))[1]

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.

(d)

$\mathrm{CH}_3$(CH$_2$)$_3$CO$_2$H is a colourless liquid with an unpleasant odour. It reacts with methanol in the presence of an acid catalyst to give an organic product V, which has a pleasant fruity smell.

(d(i))[1]

Name V.

(d(ii))[4]

A student analysed CH$_3$(CH$_2$)$_3$CO$_2$H, 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, matches V. Explain your answer with reference to relevant features of the three spectra in the region above $1500\ \text{cm}^{-1}$.

Worked solution & mark scheme

This 21-mark question has a full step-by-step worked solution and mark scheme. One marking point: correct displayed structure of the nitrile compound

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