An ester is a compound with a -COOR functional group, characterised by a sweet, fruity smell. The first part of its name comes from the alcohol and the second from the carboxylic acid.

What reagents and conditions are required for esterification?

A carboxylic acid and an alcohol are heated under reflux with concentrated H 2 SO 4 as a catalyst. The reaction is a condensation reaction that also produces water.

True or False? Hydrolysis of an ester with dilute acid is an irreversible reaction.

False. Acid hydrolysis of an ester is reversible — an equilibrium is established. Only alkaline hydrolysis is irreversible.

When propanol reacts with ethanoic acid, the ester formed is .......... . The first part of the name comes from the .......... .

When propanol reacts with ethanoic acid, the ester formed is propyl ethanoate . The first part of the name comes from the alcohol .

What products are formed when an ester undergoes alkaline hydrolysis, and what additional step is needed to obtain the carboxylic acid?

Alkaline hydrolysis produces a sodium carboxylate salt and an alcohol . The carboxylate ion (-COO - ) must then be acidified (e.g. with HCl) to produce the free carboxylic acid.

True or False? Alkaline hydrolysis of an ester is irreversible because the carboxylate salt formed cannot readily re-form the ester.

True. Alkaline hydrolysis is irreversible. The ester is fully broken down to a sodium carboxylate salt and an alcohol. Acid hydrolysis, by contrast, is reversible.

Define acid hydrolysis of esters .

An acid hydrolysis of esters is a reversible reaction in which an ester is heated under reflux with dilute acid, reforming the carboxylic acid and alcohol in an equilibrium mixture.

After alkaline hydrolysis of an ester, the sodium carboxylate salt must be .......... with an acid to convert the .......... ion into a carboxylic acid.

After alkaline hydrolysis of an ester, the sodium carboxylate salt must be acidified with an acid to convert the carboxylate ion into a carboxylic acid.

Ethanol and propanoic acid react together. Name the ester formed and the small molecule eliminated.

The ester formed is ethyl propanoate . The small molecule eliminated is water (H 2 O), as this is a condensation reaction.

A LevelChemistryCambridge (CIE)Flashcards18. Carboxylic Acids & DerivativesEsters

Esters (Cambridge (CIE) A Level Chemistry): Flashcards

Exam code: 9701

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Define ester.

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Cards in this collection (9)

Define ester.
An ester is a compound with a -COOR functional group, characterised by a sweet, fruity smell. The first part of its name comes from the alcohol and the second from the carboxylic acid.
What reagents and conditions are required for esterification?
A carboxylic acid and an alcohol are heated under reflux with concentrated H₂SO₄ as a catalyst. The reaction is a condensation reaction that also produces water.
True or False?
Hydrolysis of an ester with dilute acid is an irreversible reaction.
False.
Acid hydrolysis of an ester is reversible — an equilibrium is established. Only alkaline hydrolysis is irreversible.
When propanol reacts with ethanoic acid, the ester formed is ........... The first part of the name comes from the .......... .
When propanol reacts with ethanoic acid, the ester formed is propyl ethanoate. The first part of the name comes from the alcohol.
What products are formed when an ester undergoes alkaline hydrolysis, and what additional step is needed to obtain the carboxylic acid?
Alkaline hydrolysis produces a sodium carboxylate salt and an alcohol. The carboxylate ion (-COO^-) must then be acidified (e.g. with HCl) to produce the free carboxylic acid.
True or False?
Alkaline hydrolysis of an ester is irreversible because the carboxylate salt formed cannot readily re-form the ester.
True.
Alkaline hydrolysis is irreversible. The ester is fully broken down to a sodium carboxylate salt and an alcohol. Acid hydrolysis, by contrast, is reversible.
Define acid hydrolysis of esters.
An acid hydrolysis of esters is a reversible reaction in which an ester is heated under reflux with dilute acid, reforming the carboxylic acid and alcohol in an equilibrium mixture.
After alkaline hydrolysis of an ester, the sodium carboxylate salt must be .......... with an acid to convert the .......... ion into a carboxylic acid.
After alkaline hydrolysis of an ester, the sodium carboxylate salt must be acidified with an acid to convert the carboxylate ion into a carboxylic acid.
Ethanol and propanoic acid react together. Name the ester formed and the small molecule eliminated.
The ester formed is ethyl propanoate. The small molecule eliminated is water (H₂O), as this is a condensation reaction.

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