Chapter 9 Multiple Choice Questions

. With which of the following can ethyl ethanoate not undergo a substitution reaction?

aqueous NaOH

CH₃OH, H⁺

aqueous NH₃

CH₃CO₂Na

. With which of the following can ethanoic anhydride not undergo a substitution reaction?

aqueous NaOH

CH₃OH

NaCl in CH₃CO₂H

CH₃NH₂

. Which of the following is the most reactive in dilute aqueous NaOH?

. Which of the following is the least reactive in dilute aqueous NaOH?

. Which of the following is the most reactive towards methylamine?

. Which of the following esters is the most reactive in acid-catalysed hydrolysis?

. Which of the following esters is the most reactive in alkaline hydrolysis?

. Which of the following esters is the least reactive in alkaline hydrolysis?

. Which of (a)-(d) indicates correctly the only organic product(s) containing the ¹⁸O isotope when ethyl ethanoate is hydrolysed in an alkaline solution containing ¹⁸O-labelled water, and neutralized with dilute hydrochloric acid?

Et¹⁸OH

. Which of the following statements is wrong?

For the synthesis of esters from carboxylic acids and alcohols, we can often use a base as a catalyst.

For the synthesis of esters from carboxylic acids and alcohols, we can often use an additional acid as a catalyst.

For the alkaline hydrolysis of carboxylic esters, we need to use an excess of base.

For the hydrolysis of carboxylic esters under acidic conditions, we need only a catalytic amount of an additional acid.

. Which of the following is most reactive towards ethyl ethanoate?

CH₃OH

CH₃O^-

CH₃NH₂

CH₃CO₂^-

. Which of the following is the most reactive in ethanol containing sodium ethoxide?

. Which of the following is the second most reactive in ethanol containing sodium ethoxide?

. Which of the following esters is most reactive in alkaline hydrolysis?

. Which of the following esters is the least reactive in alkaline hydrolysis?

. Which of the following within a tetrahedral intermediate leaves most readily as a nucleofuge?

OH

OCH₂CH₃

OCOCH₃

NH₂

. Which of the following tetrahedral intermediates (formed in nucleophilic substitution reactions of carboxylic acid derivatives) gives a compound not obtained from others as a main product?

. Which stage of the following reaction scheme for the acid-catalysed hydrolysis of an ester does not correctly show the flow of electrons?

Stage (1)

Stage (2)

Stage (3)

Stage (4)

. Which of the following statements regarding acid-catalysed hydrolysis of carboxylic esters is wrong?

Protonation of the carbonyl oxygen enhances its electrophilicity.

Hydroxide ion adds to the protonated carbonyl group.

Protonation of the alkoxy oxygen of the tetrahedral intermediate facilitates elimination of the alcohol.

The initially formed protonated carboxylic acid is deprotonated to give the final product.

. Which of the following statements regarding the hydrolysis of labelled ethyl ethanoates, 1 or 2, in normal water is wrong?

During the alkaline hydrolysis of 1, unlabelled ethyl ethanoate can be recovered.

During the acid hydrolysis of 1, unlabelled ethyl ethanoate can be recovered.

The product ethanoic acid contains the ¹⁸O isotope in acid hydrolysis of both 1 and 2.

The product ethanol contains the ¹⁸O isotope in alkaline hydrolysis of 2.

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