Chapter 17 Multiple Choice Questions

. Which of the following is the structure of the most stable enol form of 2-methylpentan-3-one?

. Which enolate derived from 1-phenylbutan-2-one is most stable?

. Which enol form of the following dicarbonyl compound is predominant at equilibrium?

. Which of the following is the least abundant aldol adduct formed from an equimolar mixture of ethanal and propanone in aqueous NaOH solution?

. Which combination of carbonyl compounds gives phenyl vinyl ketone by an aldol condensation?

. Which ester will not give a good yield of the Claisen condensation product with NaOEt in EtOH?

. The following scheme shows a mechanism for the α-bromination of a methyl ketone with bromine in ethanoic acid. In which stage do the curly arrows wrongly show the flow of electrons?

. An acetoacetic ester synthesis of a ketone proceeds by alkylation of the enolate of the acetoacetic ester followed by ester hydrolysis and decarboxylation of the β-ketoacid. Which of the following methyl ketones is difficult to prepare by this method?

. A malonic ester synthesis of a carboxylic acid proceeds by alkylation of the enolate of the malonic ester followed by ester hydrolysis and decarboxylation of the β-dicarboxylic acid. Which of the following carboxylic acids is difficult to prepare by this method?

. In which of the following equations is the main product wrong?

. Which of the following is the most stable enolate derived from 4-methylhexan-3-one?

. Which enol form of ethyl 3-oxobutanoate is predominant at equilibrium?

. Which is the main product of the following reaction?

. Which is a wrong structure as a resonance contributor to the most stable enolate form of pentan-2,4-dione?

. Which of the following is the main product when one mole of propanone and two moles of benzaldehyde react in the presence of catalytic NaOH?

. Which is the main product of the following reaction?

. Which of the following reactions show a correct main product?

. The scheme below outlines a mechanism for the synthesis of a ketone (hex-5-en-2-one) from ethyl 3-oxobutanoate (an acetoacetic ester ketone synthesis). In which stage do the curly arrows wrongly show the flow of electrons?

. Which of the following equations does not indicate the correct main product(s)?

. Which of the following statements is wrong?

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