Question 1

Which of the following statements best describes the difference between an aldose and a ketose carbohydrate?

Accepted Answer

Aldoses have an aldehyde functional group, while ketoses have a ketone functional group.

Question 2

Which of the following is the correct general formula for a monosaccharide carbohydrate?

Accepted Answer

$$\mathrm{C}_n\mathrm{H}_{2n}\mathrm{O}_n$$

Question 3

Which reaction is commonly used to convert a carboxylic acid into its corresponding ester?

Accepted Answer

Fischer esterification

Question 4

A student treats ethanoic acid ($$\mathrm{CH}_3\mathrm{COOH}) $$with thionyl chloride ($$\mathrm{SOCl}_2). $$What is the major product?

Accepted Answer

Acetyl chloride ($$\mathrm{CH}_3\mathrm{COCl})$$

Question 5

Which of the following is the correct order of reactivity of carboxylic acid derivatives towards nucleophilic acyl substitution?

Accepted Answer

Acid chloride \u003e Anhydride \u003e Ester \u003e Amide

Question 6

Which of the following best describes the structure of an enolate ion?

Accepted Answer

A resonance-stabilized ion with negative charge delocalized between oxygen and alpha carbon.

Question 7

Which of the following reactions involves the formation of an enamine intermediate?

Accepted Answer

Stork enamine alkylation

Question 8

A carbohydrate undergoes mutarotation in aqueous solution. What is happening at the molecular level?

Accepted Answer

The carbohydrate interconverts between its alpha and beta anomeric forms.

Question 9

Which of the following is a correct statement about the acidity of carboxylic acids?

Accepted Answer

Carboxylic acids are more acidic than alcohols because the carboxylate ion is resonance stabilized.

Question 10

Which of the following best explains why esters are less reactive than acid chlorides in nucleophilic acyl substitution?

Accepted Answer

Esters have a more stable resonance structure, making the carbonyl less electrophilic.

Question 11

Which of the following is a correct representation of the keto-enol tautomerism for acetone?

Accepted Answer

$$\mathrm{CH}_3\mathrm{COCH}_3 \rightleftharpoons \mathrm{CH}_2=\mathrm{C}(OH)\mathrm{CH}_3$$

Question 12

A student wants to synthesize an amide from a carboxylic acid. Which reagent would be most effective?

Accepted Answer

Thionyl chloride ($$\mathrm{SOCl}_2) $$followed by ammonia ($$\mathrm{NH}_3)$$

Question 13

Which of the following is a correct statement about the formation of enolates?

Accepted Answer

Enolates are formed by the deprotonation of the alpha hydrogen of a carbonyl compound.

Question 14

Which of the following best describes the role of enolates in the aldol reaction?

Accepted Answer

Enolates act as nucleophiles attacking another carbonyl compound.

Question 15

Which of the following is a correct statement about the hydrolysis of esters?

Accepted Answer

Hydrolysis of esters produces a carboxylic acid and an alcohol.

Question 16

Which of the following is the correct product when glucose is oxidized with bromine water?

Accepted Answer

Gluconic acid

Question 17

Which of the following is a correct statement about the formation of cyclic hemiacetals in carbohydrates?

Accepted Answer

Cyclic hemiacetals are formed when the carbonyl group reacts with a hydroxyl group on the same molecule.

Question 18

Which of the following best explains why the alpha hydrogen of a carbonyl compound is acidic?

Accepted Answer

The alpha hydrogen is adjacent to a carbonyl group, and the resulting enolate ion is stabilized by resonance.

Organic Chemistry: Carbohydrates, Carboxylic Acids, and Enolates/Enols/Enamines

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