Chemistry 9701 · AS & A Level · Hydrocarbons

Hydrocarbons — practice question

The table presents the structural formulae of four compounds, A, B, C and D, with molecular formula $\text{C}_4\text{H}_8$.
(a(i))[4]

Fill in the table by writing the systematic name for A, B, C and D.

(a(ii))[1]

Explain what is meant by the term stereoisomerism.

(b(i))[1]

W is an alkene with formula $\text{C}_4\text{H}_8$. On reaction with HBr it can form two carbocations, $\text{CH}_3\text{C}^+(\text{H})(\text{CH}_2\text{CH}_3)$ and $\text{H}_2\text{C}^+\text{CH}_2\text{CH}_2\text{CH}_3$. Identify W as compound A, B, C or D.

(b(ii))[3]

Draw the skeletal formula of the major organic product made when HBr reacts with W. Explain why this product is the major organic product.

(c)[1]

A sample of propan-1-ol reacts with concentrated sulfuric acid to form propene. Identify the role of concentrated sulfuric acid in this reaction.

(d(i))[1]

Alcohol Y reacts completely when warmed with acidified $\text{Cr}_2\text{O}_7^{2-}$ to form Z. Z is distilled from the reaction mixture as soon as it forms. Tollens’ reagent is then added to a sample of Z and warmed. A silver mirror appears. Name the type of reaction that occurs when Y is converted into Z.

(d(ii))[1]

Use a tick (✓) to identify the functional group(s) present in Z.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: A correctly identified as but-1-ene / 1-butene

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