6.1.3 - Carboxylic Acids and Esters

Question 1

What is the functional group
of a carboxylic acid?

Answer 1

-COOH (C=O and C-OH)

Question 2

How do you name
carboxylic acids?

Answer 2

-oic acid

Question 3

Are carboxylic acids soluble
in water? Why? What
influences their solubility.

Answer 3

Yes. Acid group can form hydrogen bonds with
water molecules

Question 4

What are the intermolecular
forces in carboxylic acids?

Answer 4

Hydrogen bonds in solid state - very strong.

Question 4

What are esters (what are they
formed from)? Functional
group, general formula?

Answer 4

Formed from carboxylic acids and alcohols.
RCOOR’ (C=O, C-O-C)

Question 5

Write an equation for the
reaction of ethanoic acid
with propan-1-ol

Answer 5

CH₃COOH + CH₃CH₂CH₂OH → CH₃COOCH₂CH₂CH₃ + H₂O

Question 6

How do you name esters?

Answer 6

Start with the alcohol group that has replaced the
hydrogen, then acid part e.g. propyl (from
alcohol) ethanoate (from carboxylic acid).

Question 7

What characteristic physical
properties do esters have?

Answer 7

Volatile, pleasant fruity smells e.g. apple, pear
drops

Question 8

What are some uses of
esters?

Answer 8

Flavourings, perfumes (both for longer chains),
solvents (short chains), plasticisers.

Question 9

How could you distinguish
carboxylic acids from other
-OH containing
compounds?

Answer 9

Add NaHCO₃
acids will produce sodium
salt, water and carbon dioxide.

Question 10

Write an equation for the
reaction of ethanoic acid
with NaOH

Answer 10

CH₃COOH + NaOH → H₂O + CH₃COO-Na+

Question 11

Write an equation for the
reaction of ethanoic acid
with Na₂CO₃
.

Answer 11

2CH₃COOH + Na₂CO₃ → 2CH₃COO-Na+ + H₂O + CO₂

Question 12

Write an equation for the reaction of
ethanoic acid with calcium oxide

Answer 12

2CH₃COOH + CaO → (CH₃COO)₂Ca + H₂O

Question 13

What catalyst is needed for
the formation of esters from
alcohols and carboxylic
acids?

Answer 13

Concentrated strong acid e.g. H₂SO₄

Question 14

What catalyst is needed for
the hydrolysis of esters?

Answer 14

Dilute strong acid e.g. H₂SO₄

Question 15

What is an alternative
method of hydrolysis?

Answer 15

Base hydrolysis

Question 16

What are the advantages of
base hydrolysis?

Answer 16

Reaction goes to completion due to neutralisation
by base - more product in the mixture than acid
catalysed hydrolysis.

Question 17

What are carboxylic acid
derivatives?

Answer 17

Molecules that have the acyl group as part of
their structure, formed from carboxylic acids

Question 18

Name two acid derivatives
and give their functional
groups

Answer 18

Acyl chlorides: RCOCl
Acid anhydrides: RCOOCR / (RCO)2O

Question 19

How do you form an acyl
chloride?

Answer 19

React a carboxylic acids with SOCl₂

Question 20

If the nucleophile is
ammonia for the acylation of
acyl chlorides or acid
anhydrides, what are the
products of the reaction?

Answer 20

An amide

Question 21

Write an equation for the
reaction of ethanoyl chloride
and ammonia.

Answer 21

CH₃COCl + 2NH₃ → CH₃CONH₂ + NH₄Cl

Question 22

Write an equation for the
reaction of ethanoyl chloride
and ammonia.

Answer 22

CH3COCl + 2NH3
→ CH3CONH2
+
NH4Cl

Question 23

If the nucleophile is a
primary amine, what are the
products of the acylation of
acyl chlorides or acid
anhydrides?

Answer 23

N-substituted amide

Question 24

Write an equation for the
reaction of ethanoyl chloride
and methylamine

Answer 24

CH₃COCl + CH₃NH₂ → CH₃CONHCH₃ + CH₃NH₃Cl

Question 25

If the nucleophile is an
alcohol, what are the
products of the acylation of
acyl chlorides or acid
anhydrides?

Answer 25

An ester

Question 26

Write an equation for the
reaction of ethanoyl chloride
and ethanol.

Answer 26

CH₃COCl + CH₃CH₂OH → CH₃COOCH₂CH₃ + HCl

Question 27

If the nucleophile is water,
what are the products of the
acylation of acyl chlorides or
acid anhydrides?

Answer 27

Carboxylic acid (hydrolysis produces an
ester linkage)

Question 28

What is the name of this
reaction (the acylation of
acyl chlorides/acid
anhydrides with water as a
nucleophile)?

Answer 28

hydrolysis

Question 29

Write an equation for the
reaction of ethanoyl chloride
and water..

Answer 29

CH₃COCl + H₂O → CH₃COOH + HCl