Aldehydes and Ketones: Structure, Properties, and Reactions

Question 1

Which of the following reagents can be used to oxidize an aldehyde to a carboxylic acid?

Accepted Answer

KMnO4

Answer

LiAlH4

Answer

NaBH4

Answer

H2/Pd

Question 2

What is the product of the reaction between an aldehyde and a Grignard reagent?

Accepted Answer

Ketone

Answer

Alcohol

Answer

Ether

Answer

Alkene

Question 3

Which of the following is a characteristic IR absorption band for aldehydes?

Accepted Answer

C=O stretch at 1710-1740 cm-1

Answer

C-H stretch at 2920-2960 cm-1

Answer

C-O stretch at 1000-1200 cm-1

Answer

O-H stretch at 3000-3600 cm-1

Question 4

What is the major product of the reaction between an aldehyde and a primary amine?

Accepted Answer

Imine

Answer

Enol

Answer

Ketone

Answer

Amide

Question 5

Which of the following is a ketoaldehyde?

Accepted Answer

Glyceraldehyde

Answer

Formaldehyde

Answer

Acetaldehyde

Answer

Acetone

Question 6

Which of the following is a common reducing agent used in aldehyde reactions?

Accepted Answer

Sodium borohydride (NaBH4)

Answer

Manganese dioxide (MnO2)

Answer

Potassium permanganate (KMnO4)

Answer

Pyridinium chlorochromate (PCC)

Question 7

What is the product of the following reaction:
RCHO + HCN

Accepted Answer

RCH(OH)CN

Answer

RCN

Answer

RCH=NCN

Answer

RCOOCN

Question 8

The aldol condensation reaction involves the reaction of two molecules of:

Accepted Answer

Aldehydes or ketones

Answer

Ketones

Answer

Esters

Answer

Acids

Question 9

What is the major product of the following reaction:
(CH3)2C=O + CH3MgBr

Accepted Answer

(CH3)3COH

Answer

(CH3)3CBr

Answer

(CH3)2CHOH

Answer

No reaction

Question 10

The Cannizzaro reaction is a disproportionation reaction that occurs with:

Accepted Answer

Aldehydes without alpha-hydrogens

Answer

Ketones

Answer

Esters

Answer

Acids

Question 11

In the Cannizzaro reaction, what products are formed when an aromatic aldehyde is used?

Accepted Answer

Alcohol and carboxylic acid

Answer

Alcohol and aldehyde

Answer

Ketone and alcohol

Question 12

Which functional group is unique to aldehydes and not found in ketones?

Accepted Answer

Aldehyde group

Answer

Carbonyl group

Answer

Hydroxyl group

Answer

Ketone group

Question 13

Which reagent is most effective for oxidizing a primary alcohol to an aldehyde?

Accepted Answer

CrO3 in acidic medium

Answer

KMnO4

Answer

NaBH4

Answer

LiAlH4

Question 14

Identify the product of the following reaction:

CH3CH2CH2CHO + HCN

Accepted Answer

CH3CH2CH2CH(OH)CN

Answer

CH3CH2CH2COOH

Answer

CH3CH2CH2CH2OH

Answer

CH3CH2CH2CH(NH2)CN

Question 15

Which compound undergoes the Cannizzaro reaction?

Accepted Answer

Benzaldehyde

Answer

Acetone

Answer

Formaldehyde

Answer

Cyclohexanone

Question 16

Which reaction is characteristic of aldehydes and ketones?

Accepted Answer

Aldol condensation

Answer

Epoxidation

Answer

Hydroboration

Answer

Diels-Alder reaction

Question 17

Determine the hybridization of the carbon atom in the carbonyl group of an aldehyde.

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 18

Which spectroscopic technique is suitable for identifying the presence of a carbonyl group?

Accepted Answer

Infrared spectroscopy

Answer

UV-Vis spectroscopy

Answer

NMR spectroscopy

Answer

Mass spectrometry

Question 19

Identify the major product of the following reaction:

CH3CH2CHO + CH3MgBr

Accepted Answer

CH3CH2CH(OH)CH3

Answer

CH3CH2CH2OMgBr

Answer

CH3CH2CH=CH2

Answer

CH3CH2COOH

Question 20

Determine the product of the following reaction:

CH3COCH3 + NH2OH

Accepted Answer

CH3COCH=NOH

Answer

CH3CH(OH)CH=NOH

Answer

CH3COCH2NH2

Answer

CH3CH2COCH3

Question 21

What is the hybridization state of the carbon atom in the carbonyl group of a ketone? [USA, University, Biology, 20]

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 22

Which of the following reagents can be used to distinguish between an aldehyde and a ketone? [USA, University, Biology, 20]

Accepted Answer

Tollens' reagent

Answer

Benedict's reagent

Answer

2,4-dinitrophenylhydrazine

Answer

Sodium borohydride

Question 23

What is the product of the reaction between an aldehyde and an alcohol in the presence of an acid catalyst? [USA, University, Biology, 20]

Accepted Answer

Hemiacetal

Answer

Acetal

Answer

Ketal

Answer

Ether

Question 24

Which of the following statements about the reactivity of aldehydes and ketones is correct? [USA, University, Biology, 20]

Accepted Answer

Aldehydes are more reactive than ketones due to the presence of an alpha-hydrogen.

Answer

Ketones are more reactive than aldehydes because they have two carbonyl groups.

Answer

Aldehydes and ketones have similar reactivity.

Answer

Aldehydes are less reactive than ketones because they are more stable.

Question 25

Which of the following compounds is a cyclic ketone? [USA, University, Biology, 20]

Accepted Answer

Cyclohexanone

Answer

Acetophenone

Answer

Ethyl methyl ketone

Answer

Butyraldehyde

Question 26

What is the primary product formed from the reaction between an aldehyde and a primary alcohol in the presence of an acid catalyst?

Accepted Answer

A hemiacetal

Answer

An acetal

Answer

A ketal

Answer

An enol

Question 27

Provide the IUPAC name for the compound: CH3CH2CH(CH3)CHO

Accepted Answer

3-Methylbutanal

Answer

2-Methylpropanal

Answer

3-Methyl-2-butanone

Answer

2-Methyl-3-butanone

Question 28

Which of the following is a cyclic ketone?

Accepted Answer

Cyclohexanone

Answer

2-Butanone

Answer

Acetaldehyde

Answer

Benzaldehyde

Question 29

Provide the correct general structure of an aldehyde.

Accepted Answer

R-CHO

Answer

R-COOH

Answer

R-CH2OH

Answer

R-COOR

Question 30

Which of the following reactions is characteristic of both aldehydes and ketones and involves the addition of a nucleophile to the carbonyl carbon?

Accepted Answer

Nucleophilic addition

Answer

Electrophilic addition

Answer

Substitution

Answer

Elimination

Question 31

What is the product of the oxidation of a primary alcohol by an oxidizing agent such as chromic acid?

Accepted Answer

Aldehyde

Answer

Ketone

Answer

Carboxylic acid

Answer

Ester

Question 32

Which of the following reagents, when used in a reaction with an unknown carbonyl compound, can differentiate between an aldehyde and a ketone based on their reactivity?

Accepted Answer

Tollens' reagent

Answer

Benedict's reagent

Answer

Grignard reagent

Answer

Hydrogen cyanide

Question 33

What is the major product formed when an aldehyde undergoes reduction using a reducing agent such as sodium borohydride?

Accepted Answer

Primary alcohol

Answer

Secondary alcohol

Answer

Tertiary alcohol

Answer

Ketone

Question 34

Identify the functional group that is common to both α,β-unsaturated aldehydes and α,β-unsaturated ketones.

Accepted Answer

Alkene group

Answer

Carbonyl group

Answer

Alcohol group

Answer

Ether group

Question 35

Which of the following compounds exhibits the highest reactivity towards nucleophilic addition reactions due to the presence of an unsubstituted carbonyl group?

Accepted Answer

Formaldehyde

Answer

Acetaldehyde

Answer

Acetone

Answer

Benzophenone

Question 36

Provide the IUPAC name for the following compound: CH3CH2CH(CH3)CHO.

Accepted Answer

2-Methylbutanal

Answer

3-Methylbutanal

Answer

2-Ethylpropanal

Answer

3-Ethylpropanal

Question 37

Which of the following aldehydes has the highest boiling point, considering the intermolecular forces present?

Accepted Answer

Butyraldehyde

Answer

Formaldehyde

Answer

Acetaldehyde

Answer

Propionaldehyde

Question 38

Which statement accurately describes the relative reactivity of aldehydes and ketones?

Accepted Answer

The reactivity of aldehydes and ketones depends on the specific substituents attached to them.

Answer

Aldehydes are generally more reactive than ketones.

Answer

Ketones are generally more reactive than aldehydes.

Answer

Aldehydes and ketones have similar reactivity.

Question 39

In NMR spectroscopy, which signal can be used to distinguish between an aldehyde and a ketone?

Accepted Answer

Singlet at around 9-10 ppm

Answer

Triplet at around 2-3 ppm

Answer

Quartet at around 1-2 ppm

Question 40

**Clarity Improvement**: Which of the following compounds is classified as an aldehyde? An aldehyde contains a carbonyl group bonded to at least one hydrogen atom.

Accepted Answer

CH3CHO

Answer

CH3CH2OH

Answer

CH3COCH3

Answer

CH3COOH

Question 41

Identify the major product formed from the reaction between an aldehyde and a primary amine.

Accepted Answer

An imine

Answer

An amide

Answer

A hemiaminal

Answer

A hydrazone

Question 42

Which of the following IR absorption frequencies (in wavenumbers) is characteristic of the carbonyl group in aldehydes?

Accepted Answer

1720-1740 cm-1

Answer

3400-3600 cm-1

Answer

2800-3000 cm-1

Answer

1650-1690 cm-1

Question 43

Provide the IUPAC name for the compound: CH3CH2CH2CHO.

Accepted Answer

Butanal

Answer

Butanone

Answer

Pentanal

Question 44

Which of the following reagents can be used to oxidize aldehydes selectively to carboxylic acids?

Accepted Answer

KMnO4

Answer

NaBH4

Answer

Zn(Hg)/HCl

Answer

LiAlH4

Question 45

What is the product of the reaction between an aldehyde and a thiol (R-SH)?

Accepted Answer

A thioacetal

Answer

An acetal

Answer

An ester

Answer

A hemiacetal

Question 46

Which of the following compounds is classified as a ketone? A ketone contains a carbonyl group bonded to two carbon atoms.

Accepted Answer

CH3COCH3

Answer

CH3COOH

Answer

CH3CH2OH

Answer

CH3CHO

Question 47

Which of the following statements accurately describes the structural difference between aldehydes and ketones?

Accepted Answer

Aldehydes have a terminal -CHO group, while ketones have a -CO- group bonded to two carbon atoms.

Answer

Aldehydes have a -CO- group, while ketones have a terminal -CHO group.

Answer

Both aldehydes and ketones have a -CHO group.

Question 48

What is the hybridization state of the carbonyl carbon in an aldehyde?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Question 49

Which reaction is unique to aldehydes and not ketones?

Accepted Answer

Tollens' test (formation of a silver mirror)

Answer

Oxidation with KMnO4 (formation of carboxylic acid)

Answer

Reduction with NaBH4 (formation of primary alcohol)

Answer

Reaction with Grignard reagents (formation of tertiary alcohol)

Question 50

What is the product of the reaction between an aldehyde and a primary amine?

Accepted Answer

Imine

Answer

Amide

Answer

Enamine

Answer

Nitrile

Question 51

Which statement accurately describes the reactivity of ketones compared to aldehydes?

Accepted Answer

Ketones are generally less reactive than aldehydes in nucleophilic addition reactions.

Answer

Ketones and aldehydes have similar reactivity in nucleophilic addition reactions.

Answer

Ketones are more reactive than aldehydes in nucleophilic addition reactions.

Question 52

Identify the cyclic ketone from the following compounds:

Accepted Answer

Cyclohexanone

Answer

Benzaldehyde

Answer

Acetone

Answer

Butanal

Question 53

Which spectroscopic technique is commonly used to distinguish between aldehydes and ketones?

Accepted Answer

Infrared spectroscopy

Answer

Nuclear magnetic resonance (NMR) spectroscopy

Answer

Mass spectrometry

Question 54

What is the common intermediate formed during the acid-catalyzed hydration of both aldehydes and ketones?

Accepted Answer

Geminal diol

Answer

Enol

Answer

Epoxide

Answer

Peroxide