Chemistry 3720: Aldehydes and ketones

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Which statement is not true of a tertiary alcohol?

1. Reacts with NaH
2. OH ~3400 cm-1 IR
3. Oxidized by PCC
4. Has pkA of ~16-18
5. Reacts with HBr

Not oxidized by PCC
When a primary alcohol is oxidized with PCC, what type of molecule is formed?

An aldehyde
Reduction of a ketone with NaBH₄ results in what type of product?

A secondary alcohol
Methylphenyl ketone will not react with which of the following?

1. NaBH₄ in CH₃OH
2. Excess CH₃OH/cat. H+
3. NaCN in HCl
4. Excess NaOH/I₂
5. PCC or PDC

The ketone will not be oxidized by PCC or PDC
Reaction of an aldehyde with RLi, followed by an acid quench, results in what type of alcohol product?

A secondary alcohol
Which reagent is used to oxidize primary alcohols to carboxylic acids; PCC, Na₂Cr₂O₇/H₂SO₄, or LiAlH₄?

Na₂Cr₂O₇/H₂SO₄
Which solvent must not be used with RLi or RMgBr reagents in addition to aldehydes or ketones; THF, ether, or CH₃OH?

CH₃OH (it has an acidic proton)
Reaction of a ketone with excess of an alcohol and a catalytic amount of acid gives what product?

1. Ester
2. Acetal
3. Ether
4. Imine
5. Alcohol

Acetal
What reagent is used to oxidize a ketone to an ester?

1. PCC or PDC
2. conc. H₂SO₄
3. m-CPBA
4. NaBH₄ in CH₃OH
5. NaIO₄ in H₂O

m-CPBA
Which of the following molecules is not a ketone?

1. 3-Pentanone.
2. Acetone
3. 2-Pentanone
4. 1-Pentanone
5. Pentanal

Pentanal (aldehyde)
What type of compound is formed during the oxidation of a primary alcohol to a carboxylic acid using Na₂Cr₂O₇/H₂SO₄?

1. An acetal
2. A ketone
3. A carboxylic acid
4. A hydrate
5. An ester

A hydrate
Which of the following is not characteristic of a typical ketone?

1. ¹³C signal at 200 ppm
2. IR signal at 1700 cm-1
3. Reaction with primary amine
4. Prefers enol form
5. Reaction with RMgBr

Most ketones do not prefer the enol form
Which of the following do not react with RMgBr?

1. Ethers
2. Aldehydes
3. Ketones
4. Carboxylic acids
5. Esters

Ethers
Which of the following could be used to conclusively distinguish propanone from propanal?

1. Iodoform test
2. IR spectroscopy
3. 13C NMR spectroscopy
4. 1H NMR spectroscopy
5. Reaction with Na₂Cr₂O₇/H₂SO₄

Iodoform test (methyl ketone), 1H NMR (9 ppm for aldehyde), oxidation with Na₂Cr₂O₇/H₂SO₄ (aldehyde yes, ketone no)
Which one of the following could not yield a primary alcohol?

1. Reduction of an aldehyde
2. Reduction of a carboxylic acid
3. Reduction of a ketone

Reduction of a ketone (gives secondary alcohol)
Which reactions below result in an aldehyde product?

1. Secondary alcohol with PCC
2. Primary alcohol with PDC
3. Primary alcohol with chromic acid
4. Carboxylic acid with LiAlH₄
5. Ketone with NaBH₄ in CH₃OH

Primary alcohol + PDC produces an aldehyde
Which methods below would not push an equilibrium from ketone to acetal?

1. Add an excess of the alcohol
2. Remove the water produced
3. Distill off the acetal product
4. Use water as the solvent
5. Distill away the ketone

Using water as the solvent and distilling away the ketone would not push the equilibrium to product
Which of the following is the best reagent for turning primary alcohols into aldehydes?

1. OsO₄ with H₂O₂
2. NaIO₄ in water
3. PCC in CH₂Cl₂
4. Na₂Cr₂O₇/H₂SO₄
5. H₂O₂ in water

PCC in CH₂Cl₂
Enolization of aldehydes and ketones is catalyzed by which of the following?

1. Ether
2. Acid
3. Ester
4. Base
5. Alcohol

Acid and base would catalyze enolization
Which would be the best technique to tell an aldehyde apart from a ketone?

1. Infra-red spectroscopy
2. 13C NMR spectroscopy
3. 1H NMR spectroscopy
4. Mass spectrometry
5. Boiling point analysis

¹H NMR spectroscopy would show a distinctive signal at 9 ppm for the aldehyde

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pnorris

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Chemistry 3720: Aldehydes and ketones

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organic chemistry

Updated

2010-05-10T00:12:15Z

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