Chapter 26.2

Question 1

carboxylic acid acidity

Answer 1

weak acids but strong enough to displace carbon dioxide from carbonates.

Question 2

carboxylic acid Solubility in Water

Answer 2

The smaller carboxylic (up to C4)
acids dissolve in water in all
proportions but after this the solubility rapidly reduces.
they dissolve because they can hydrogen bond to the water molecules.

Question 3

delocalisation in carboxylic acid salts

Answer 3

The carboxylic acid salts are stabilised by delocalisation,
which makes the dissociation more likely

Question 4

The delocalised ion has equal C-O bond lengths. why is this?

Answer 4

If delocalisation did not occur, the C=O bond would be
shorter than the C-O bond.

Question 5

The delocalisation makes the ion more stable and therefore more likely to form. how does this happen?

Answer 5

The pi charge cloud has
delocalised and spread out.

Question 6

strength of carboxylic acids trend

Answer 6

Increasing chain length pushes
electron density on to the COO- ion, making it more negative and
less stable. This makes the acid
less strong.

Question 7

chlorine on acid strength

Answer 7

Electronegative chlorine atoms
withdraw electron density from
the COOion, making it less
negative and more stable. This
make the acid more strong.

Question 8

acid + metal (Na)->

Answer 8

salt + hydrogen

Question 9

acid + alkali ->

Answer 9

salt + water

Question 10

acid + carbonate ->

Answer 10

salt + water + co2

Question 11

The effervescence caused by production of CO2
with carboxylic acids with solid Na2CO3 or
aqueous NaHCO3 can be used as

Answer 11

a functional
group test for carboxylic acids

Question 12

Oxidation: general trend and exception of methanoic acid

Answer 12

Carboxylic acids cannot be oxidised by using
oxidising agents
methanoic acid’s structure has effectively an aldehyde group

Question 13

methanoic acid oxidation forms

Answer 13

h2co3(carbonic acid) which can decompose to form co2

Question 14

carboxylic acid + alcohol + h+(sulfuric acid catalyst)

Answer 14

ester + water

Question 15

ester suffix for the second part

Answer 15

-anoate
comes from the carboxylic
acid and includes the C in
the C=O bond.

Question 16

ester suffix for first part

Answer 16

-yl
comes from the alcohol that has formed it and is next to the single bonded oxygen.

Question 17

ethanoic acid + ethanol

Answer 17

ethyl ethanoate + h2o

Question 18

the reaction to form esters is…

Answer 18

reversible and slow with a low yield

Question 19

esterification using acid anhydride

Answer 19

acid anhydride-> ester by alcohol at room temp

Question 20

The acid anhydrides are —-
reactive than carboxylic acids.
The reaction is …
and a —— yield is achieved.

Answer 20

The acid anhydrides are more
reactive than carboxylic acids.
The reaction is not reversible
and a higher yield is achieved.

Question 21

hydrolysis of esters can be done by

Answer 21

heating with acid or with sodium hydroxide.

Question 22

ester hydrolysis: acid

Answer 22

reagents: dilute acid (HCl)
conditions: heat under reflux
reverse reaction of ester formation.
forms:carboxylic acid and alcohol

Question 23

ester hydrolysis: sodium hydroxide

Answer 23

reagents: dilute sodium hydroxide
conditions: heat under refluxw

Question 24

why is ester hydrolysis with naoh not reversible- also known as saponification

Answer 24

The carboxylic acid salt product is the anion of the carboxylic acid.
The anion is resistant to attack by weak nucleophiles such as alcohols, so the reaction is not reversible.

Question 25

acyl chlorides are much more reactive than carboxylic acids, why?

Answer 25

The Cl group is classed as a good leaving groups (to do with less effective delocalisation.)

Question 26

Formation of acyl chloride from a carboxylic acid

Answer 26

Reagent: SOCl2 (Sulfur dichloride oxide (thionyl chloride)) Conditions: room temp

Question 27

reaction of acyl chloride with water

Answer 27

Change in functional group: acyl chloride-> carboxylic acid Reagent: water Conditions: room temp.

Question 28

acyl chloride with water observation

Answer 28

Steamy white fumes of HCl are given off

Question 29

acyl chloride with alcohol observation

Answer 29

Steamy white fumes of HCl are given off

Question 30

reaction of acyl chloride with alcohol

Answer 30

Change in functional group: acyl chloride -> ester Reagent: alcohol Conditions: room temp.

Question 31

Reaction of acyl chloride with ammonia

Answer 31

Change in functional group: acyl chloride -> primary amide Reagent: ammonia Conditions: room temp.

Question 32

acyl chloride with ammonia observation

Answer 32

white smoke of NH4Cl is given off

Question 33

reaction of acyl chlorides with primary amines

Answer 33

Change in functional group: acyl chloride-> secondary amide Reagent: primary amine Conditions: room temp

Question 34

reaction of acyl chloride with phenol

Answer 34

Change in functional group: acyl chloride -> ester Reagent: phenol Conditions: room temp.

Question 36

acyl chloride with phenol observation

Answer 36

Steamy white fumes of HCl are given off

Question 37

condensation reaction can also be described as

Answer 37

addition followed by elimination