CAIE A Level Chemistry 9701 · Organic synthesis

Organic synthesis: compare question

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A student proposes to prepare 2-hydroxybutanoic acid, $\ce{CH3CH2CH(OH)COOH}$ , from 1-chloropropane, $\ce{CH3CH2CH2Cl}$ , using the following three-step route.

Step 1: 1-chloropropane is heated with aqueous sodium hydroxide to form compound A.

Step 2: compound A is warmed with acidified potassium dichromate(VI), the product being distilled off as it forms, to give compound B.

Step 3: compound B is treated with hydrogen cyanide, $\ce{HCN}$ , followed by dilute hydrochloric acid.

Compare the organic chemistry of Steps 1 and 2 with that of Step 3. In your answer, refer to the functional groups of the compounds A, B and the final product, the type of reaction in each step, and the reagents and conditions used.

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Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.

Organic synthesis: compare question

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