26.4- REACTIONS OF CARBOXYLIC ACIDS AND ESTERS

Question 1

Is the carboxylic acid polarised?

Answer 1

yes

Question 2

What is the C𝛿+ open to be attacked by? (reactivity of carboxylic acids)

Answer 2

open to attack from nucleophiles

Question 3

What may the O𝛿- of the C=O be attacked by?

Answer 3

positively charged species

Question 4

What can the H𝛿+ be lost as?

Answer 4

H+, in which case compound behaving like acid

Question 5

If the hydrogen of the -COOH is lost, what is left?

Answer 5

negative ion- carboxylate ion

Question 6

On the carboxylate ion, where is the negative charge?

Answer 6

shared over whole of carboxylate group

Question 7

What does the delocalisation do to the carboxylate ions?

Answer 7

makes resulting ion more stable

Question 8

What distinguishes carboxylic acids from other organic compounds that contain the -OH group, such as alcohols?

Answer 8

they’re strong enough to react with sodium hydrogencarbonate, NaHCO3

Question 9

What are carboxylic acids in terms of protons?

Answer 9

proton donors

Question 10

What do carboxylic acids form with more reactive metals, alkalis, metals oxides or metal carbonates?

Answer 10

ionic salts

Question 11

What is the general name of the ionic salts named as when carboxylic acids react with more reactive metals, alkalis, metals oxides or metal carbonates?

Answer 11

carboxylates

Question 12

What are esters in terms of acids?

Answer 12

acid derivatives

Question 13

What reacts with carboxylic acids to form esters?

Answer 13

alcohols

Question 14

What is the reaction between carboxylic acids + alcohols sped up by?

Answer 14

strong acid catalyst

Question 15

What charge does the carbonyl carbon atom of an ester have and what does this mean?

Answer 15

𝛿+ charge and is therefore attacked by water acting as weak nucleophile

Question 16

Does the hydrolysis of water go to completion?

Answer 16

no

Question 17

What does the hydrolysis of esters produce?

Answer 17

mixture containing ester, water, acid + alcohol

Question 18

When can an ester be hydrolysed at room temp?

Answer 18

when strong acid catalyst used

Question 19

Other than acids, what else catalyse the hydrolysis of esters?

Answer 19

bases

Question 20

When vases catalyse the hydrolysis of esters, what is produced?

Answer 20

salt of acid rather than acid itself

Question 21

As the acid is removed from the reaction when a base catalyses the hydrolysis of an ester, what happens?

Answer 21

equilibrium not established + reaction goes to completion, so more product in mixture

Question 22

How many carboxylic acids do oils and fats have and what are they called?

Answer 22

3 molecules of long chain carboxylic acids called fatty acids

Question 23

What are fats and oils based on?

Answer 23

glycerol

Question 24

As fats and oils are based on glycerol are based on glycerol, what are they referred to as?

Answer 24

triglycerides

Question 25

What can fats and oils be hydrolysed in acid conditions to give?

Answer 25

mixture of glycerol + component of fatty acids

Question 26

How else can fats and oils be hydrolysed, other than in acid conditions?

Answer 26

by boiling with sodium hydroxide

Question 27

When fats and oils are hydrolysed by boiling them with sodium hydroxide, what is produced?

Answer 27

glycerol and mixture of sodium salts of the three acids which formed part of the ester

Question 28

What is the mixture of sodium salts produced when fats and oils are hydrolysed by boiling them with sodium hydroxide?

Answer 28

soaps

Question 29

What can soap be a mixture containing?

Answer 29

mixture containing many different salts

Question 30

What does the type of soap depend on?

Answer 30

depends on fatty acids initially present in ester

Question 31

Why does glycerol readily form hydrogen bonds?

Answer 31

as it has three O-H bonds

Question 32

How soluble is glycerol in water?

Answer 32

very soluble

Question 33

Why is glycerol used in many pharmaceutical + cosmetic preparations?

Answer 33

as it attracts water, it’s used to prevent ointments + creams from drying out

Question 34

Where is glycerol used as a solvent? (2)

Answer 34

medicines + toothpaste

food industry- food colourings

Question 35

Examples of things glycerol is used to plasticise? (4)

Answer 35

sheets
gaskets
cellophane
special quality papers

Question 36

Where are plasticisers introduced?

Answer 36

between molecules of polymer which makes up material + by allowing molecules to slip over each other, material becomes flexible + smooth

Question 37

What happens to plasticisers overtime?

Answer 37

leak away, leaving plastic brittle + inflexible