Chemistry 9701 · AS & A Level · Hydroxy compounds

Hydroxy compounds — practice question

Compounds that contain the allyl group, $\text{CH}_2{=}\text{CHCH}_2-$, have strong, pungent odours and occur in onions and garlic. Allyl alcohol, $\text{CH}_2{=}\text{CHCH}_2\text{OH}$, is a colourless liquid that dissolves in water.
(a(i))[1]

Give the structural formula for the organic compound produced when allyl alcohol is reacted with acidified potassium dichromate(VI) and heated under reflux.

(a(ii))[1]

Give the structural formula for the organic compound formed when allyl alcohol reacts with bromine in an inert organic solvent.

(a(iii))[1]

Give the structural formula for the organic compound formed when allyl alcohol is reacted with cold, dilute, acidified potassium manganate(VII).

(a(iv))[2]

Give the structural formula for the organic compound formed when allyl alcohol is reacted with hot, concentrated, acidified potassium manganate(VII).

(b(i))[1]

When allyl alcohol reacts with concentrated HCl at $100\,^{\circ}\text{C}$, $\text{CH}_2{=}\text{CHCH}_2\text{Cl}$ is produced. State as fully as you can what type of reaction this is.

(b(ii))[1]

When allyl alcohol is reacted with $\text{MnO}_2$ at room temperature, $\text{CH}_2{=}\text{CHCHO}$ is formed. What type of reaction is this?

(a)[5]

Allyl alcohol acts both as a primary alcohol and as an alkene. Give the structural formula of the organic product formed when allyl alcohol is reacted separately with each of the reagents below.

(b)[2]

Allyl alcohol undergoes the reactions below.

(c)[5]

Allyl alcohol can be changed into propanal in two steps: $\text{CH}_2{=}\text{CHCH}_2\text{OH} \rightarrow \text{CH}_3\text{CH}_2\text{CH}_2\text{OH} \rightarrow \text{CH}_3\text{CH}_2\text{CHO}$.

(c(i))

What reagents and conditions should be used for each step? Give the reagent(s) and condition(s) for step I and step II.

(c(ii))

Allyl alcohol and propanal are isomers. What form of isomerism do they show?

(d)[1]

Allyl alcohol can also be turned into propanal using a ruthenium(IV) catalyst in water: $\text{CH}_2{=}\text{CHCH}_2\text{OH} \rightarrow \text{CH}_3\text{CH}_2\text{CHO}$. Suggest what is unusual about this single-step reaction.

Worked solution & mark scheme

This 20-mark question has a full step-by-step worked solution and mark scheme. One marking point: Accepted compound: $\mathrm{CH_2=CHCO_2H}$

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