Carbonyls

Question 1

Carbonyl group

Answer 1

C=O

Question 2

Aldehyde

Answer 2

Carbonyl group on the end of carbon chain

Question 3

Ketones

Answer 3

Carbonyl joined to 2 carbon atoms

Question 4

Oxidation of aldehydes

Answer 4

Form Carboxylic acid
Acidified dichromate ion
+ [O]
Heat under reflux

Question 5

C=O bond

Answer 5

Made of sigma and pi bond
Bond is polar as oxygen is more electronegative
Allows reactions w nucleophiles due to slight +ve carbocation
NUCLEOPHILIC ADDITION

Question 6

Reducing aldehyde

Answer 6

+ 2[H]
Form primary alcohol
Require NaBH4 aq

Question 7

Reducing ketone

Answer 7

+2[H]
Form secondary alcohol
Require NaBH4 aq

Question 8

Reaction with HCN

Answer 8

Nucleophilic addition
H2SO4/NaCN (HCN too dangerous)
Hydroxynitrile formed -OH and
C triple bond N

Question 9

Mechanism for reduction

Answer 9

Lone pair on H- attracted to carbocation
Dative bond forms and put bond breaks via heterolytic fission forming O:-
Donates lone pair to hydrogen in water forms OH (protonated)

Question 10

Mechanism for NaCN/ H+

Answer 10

Lone pair of :CN- attract to carbocation dative bond forms
Pi bond breaks and forms O:-
Intermediate protonated by donating pair of electrons to H+ ion

Question 11

Detecting carbonyls

Answer 11

2-4 DNP dissolved in sulphuric acid and methanol
Yellow/ orange pp indicates carbonyl present

Question 12

Testing for aldehydes

Answer 12

Add AgNO3 to test tube and NaOH aq brown pp forms add dilute ammonia until form colourless = tollens
Add to solution and heat in water bath at 50 degrees for 10-15mins

Question 13

Carboxyl group

Answer 13

-COOH

Question 14

Carboxylic acid properties

Answer 14

Contain polar bonds - soluble in water
Weak acid only partially dissociate

Question 15

Acid reactions

Answer 15

In redox and neutralisation reactions carboxylate ion forms -COO-
Test for Carboxylic acid via neutralisation

Question 16

Acyl chloride

Answer 16

C=O
|
Cl

Question 17

Acid anhydrides

Answer 17

Removal of water from 2 carb acids

Question 18

Esters

Answer 18

Name = alcohol prefix -yl carb acid prefix - oate
Conc H2SO4 catalyst

Question 19

Acid hydrolysis of esters

Answer 19

Heated under reflux w dilute aq acid
Ester broken down via water

Question 20

Alkali hydrolysis

Answer 20

Heated under reflux w aq -OH ions
Forms alcohol and carboxylate ion

Question 21

Preparation of acyl chlorides

Answer 21

Carb acid + SOCl2 => acyl chloride + SO2(g) + HCl(g)
Fume cupboard gases harmful

Question 22

Reaction of acyl chloride and alcohol

Answer 22

Form ester and hydrogen halide
V reactive properties of acyl chlorides

Question 23

Acyl chloride+ phenol

Answer 23

Ester + hydrogen halide

Question 24

Acyl chloride + H20

Answer 24

Carboxylic acid + hydrogen halide

Question 25

Acyl chloride with ammonia

Answer 25

Nucleophilic sub
Forms primary amide and ammonium chloride

Question 26

Acyl chloride primary amine

Answer 26

Secondary amine and methylammonium chloride

Question 27

Acid anhydride + phenol

Answer 27

Ester and -oic acid