Carboxylic acids 3.3.9

Question 1

Name three reactions to prepare carboxylic acids

Answer 1

Oxidation of primary alcohol under reflux
Oxidation of aldehyde under reflux
Hydrolysis of Nitriles

Question 2

Describe the reaction (and write the equation) for hydrolysis of nitriles

Answer 2

Nitrile is refluxed with water and hydrochloric acid
Produces carboxylic acid and ammonium chloride
R-C≡N + 2H2O + HCl →RCOOH + NH4Cl

Question 3

What happens when Carboxylic acids dissociate

Answer 3

Forms a carboxylate ion RCOO- (negative) and a H+ ion

Question 4

Is dissociation of carboxylic acids reversible

Answer 4

yes

Question 5

What is the charge of a carboxylate ion

Answer 5

Negative

Question 6

Is the carboxylate ion stable or not - why?

Answer 6

Yes
Negative charge is delocalised across the whole carboxylate group

Question 7

Give the products of the reaction of methanoic acid and sodium carbonate

Answer 7

Sodium methanoate. carbon dioxide and water

Question 8

What is produced when coohs react with carbonates

Answer 8

Salt, water and CO2

Question 9

What is produced when coohs are neutralised

Answer 9

Salt and water

Question 10

What is produced when propanoic acid and sodium hydroxide are reacted together

Answer 10

Sodium propanoate and water

Question 11

What is formed when an alcohol and carboxylic acid react

Answer 11

Ester and water

Question 12

What is the functional group of an ester

Answer 12

COO

Question 13

What type of reaction occurs when an alcohol and carboxylic acid react

Answer 13

Condensation

Question 14

What are the products formed when propanoic acid reacts with methanol

Answer 14

Methyl prooanoate and water

Question 15

What is hydrolysis of esters

Answer 15

Splitting up esters using water

Question 16

What two types of hydrolysis are there

Answer 16

Base and Acid

Question 17

What acids at what strength are used in acid hydorlysis

Answer 17

Dilute HCL or H2SO4

Question 18

Ester+Water (with H+) =

Answer 18

OH and COOH

Question 19

What does acid hydrolysis produce

Answer 19

Alcohol and cabroxylic acid

Question 20

What does base hydrolysis producen

Answer 20

Carboxylate ion and alcohol

Question 21

What is the IUPAC name of glycerol

Answer 21

propane-1,2,3-triol

Question 22

In what way are fats and lipids esters of glyceorl

Answer 22

Glycerol (alcohol) reacts in a condensation to reaction with 3 fatty acids (COOH) to form fatty acids with COO

Question 23

Do saturated fatty acids have double bonds C=C

Answer 23

NO

Question 24

What is the difference between fats and oils and why

Answer 24

Fats are normally solids at room temperature but oils are liquids at room temperature
Because
Oils are polysaturated whereas fats are unsaturated
So
Molecules of fats get closer together as the chain DOES NOT bend so VdWs are stronger and so fats have a higher MP

Question 25

How is soap formed

Answer 25

Hydrolysis of animal fats or vegetable oils (heated with NaOH)

Question 26

What happens when you react a fat/oil with NaOH

Answer 26

It forms a sodium salt and glycerol

Question 27

How is biodiesel made

Answer 27

React oils with methanol (KOH catalyst)

Question 28

What is biodiesel actually

Answer 28

Methyl ester

Question 29

What is formed when yiu react oils with methanol (KOH catalyst)

Answer 29

Glycerol and methyl ester

Question 30

Functional group of acyl/acid chlorides

Answer 30

COCl

Question 31

Why are COCls susceptible to attack by nuclepphiles

Answer 31

in cocl c=o and c-cl bonds are polar

Question 32

What is the reaction called when COCls react with water, nh3 or amines

Answer 32

Addition-elimination

Question 33

What is produced when COCl reacts wtih water

Answer 33

Carboxylic acid and HCl

Question 34

What is produced when COCl reacts with NH3 nucleophile

Answer 34

alkyl amide + NH4Cl

Question 35

What is produced when COCl reacts wtih alcohol

Answer 35

Ester + HCl

Question 36

Amine vs Amide

Answer 36

Amine is MINE because its noT C=Ool

Question 37

What is produced when acid anhydrides react with water

Answer 37

Carboxylic acid

Question 38

What is produced when acid anhydrides react with alcohols

Answer 38

Ester and carboxylic acid

Question 39

What is produced when acid anhydrides react with primary amines or NH3

Answer 39

Amides

Question 40

Name The industrial advantages of ethanoic anhydride over ethanoyl chloride in the manufacture of the drug aspirin.

Answer 40

Ethanoic anhydride is cheaper than ethanoyl chloride. Ethanoic anhydride is safer to use than ethanoyl chloride. It is less corrosive and not so readily hydrolysed (its reaction with water is slower). Ethanoic anhydride doesn't produce dangerous (corrosive and poisonous) fumes of hydrogen chloride

Question 41

Describe how to purify a sample of aspirin

Answer 41

- Dissolve in minimum hot solvent - Filter -Cool in ice bath - Filter using buchner funnel -Dry