Chemistry 9701 · AS & A Level · Carbonyl compounds
Carbonyl compounds — practice question
P, Q, R and S are structural isomers with the molecular formula $\text{C}_5\text{H}_{10}$. Each of the four compounds rapidly decolourises bromine in the dark. P, R and S do not show stereoisomerism, whereas Q exists as a pair of geometrical (cis-trans) isomers. When all four compounds are treated with hot concentrated, acidified potassium manganate(VII), they give a range of products, as set out in the table. T forms an orange crystalline product with 2,4-dinitrophenylhydrazine reagent, 2,4-DNPH, but it does not react with Fehling’s reagent.
(a)[5]
State the structural formulae of P, Q, R, S and T.
(b(i))[2]
Explain what is meant by stereoisomerism.
(b(ii))[2]
Draw the displayed formulae of the geometrical isomers of Q and name both of them.
(c)[1]
Name the organic product formed when T reacts with sodium borohydride, $\text{NaBH}_4$.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$P = CH_3CH_2CH_2CH{=}CH_2$” …