TMK Chapter 16 Carbonyl Compounds

CHEMISTRY SK025
CHAPTER 16: CARBONYL COMPOUNDS

TUTORIAL

16.1: Introduction & 16.2: Nomenclature
1. (a) 4-chloro-2,4-dimethylhexanal

(b) cyclohexanone
(c) phenylethanone/acetophenone
(d) 1-phenyl-2-propanone

2. (a) (c)
CH3 O O

CH3CH2CHCHCH CH3CH2CHC CHCH3
Cl CH3
CH3CH2
(b)

CH3 O

CH3CHCH2CCH3

16.3: Preparation & 16.4: Chemical Properties

1. (a)

O
CH3CH2CH2OH PCC, CH2Cl2 CH3CH2CH

(b)

O

CH3CH2CH CHCH2CH3 i) O3 2 CH3CH2CH
ii) Zn/H3O+

2. (a) CH3CH2CH2OH
(b) CH3CH2CH(OH)C6H5
(c) CH3CH2COOH

3. (a) Brady’s test
Test

Reagent & Reagent: 2,4-dinitrophenylhydrazine

Conditions

Compound benzaldehyde benzyl alcohol

Observation A yellow/orange precipitate No yellow/orange precipitate
formed formed

H

+C O H2N NH NO2

Equation O2N

H NO2
C N NH

O2N

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CHAPTER 16: CARBONYL COMPOUNDS

(b)
Test Tollen’s test
Reagent & Reagent: [Ag(NH3)2]+ , OH−
Conditions

Compound hexanal 2-hexanone

Observation A silver mirror formed No silver mirror formed

O

+ [Ag(NH3)2]+

OH-

Equation

O

+- Ag+

O

(c)

Test Iodoform test

Reagent & Reagent: I2 in NaOH
Conditions

Compound 2-pentanone 3-pentanone

Observation A yellow precipitate formed No yellow precipitate formed

O O

Equation + I2 NaOH - + CHI3

O

4. (a) i) LiAlH4 OH
O ii) H2O CH3CH CH3

CH3C CH3 conc. H2SO4 

H2C CHCH3

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CHAPTER 16: CARBONYL COMPOUNDS

(b) OH
O i) LiAlH4 conc H2SO4

ii) H2O
KMnO 4, OH -, cold

OH

(c) i) LiAlH4 OH
ii) H2O OH
O CH3CH2CHCH2CH3

CH3CH2C CH2CH3 PCl3

Cl
CH3CH2CHCH2CH3

5. a) I : PCC, CH2Cl2 II : C6H6MgBr, ether

b) III : O3, Zn/CH3COOH IV : KCN, H⁺

c) V : 2,4- dinitrophenylhydrazine
d) VI : Ag(NH3)2+, H2O, OH−

6. A: CH3CH2CH2OH C: CH3CH2COOH
B: CH3CH2CH(OH)CH2CH3 D: CH3CH=CH2
I: PBr3 III: PCl3
II: KMnO4, H3O+, 

7. (a) A: C:
OH CH3C CH3

CH3C CH3 CHCH3
CN D: CH3CH(OH)CH3

B: SK 3
OH

CH3C CH3
CH 2CH 3

CHEMISTRY SK025
CHAPTER 16: CARBONYL COMPOUNDS

(b) Saytzeff’s rule

(c)

Test Bromine test

Reagent & Reagent: Br2 in CH2Cl2
Conditions

Compound CH3C CH3 CH3CH(OH)CH3
CHCH3
Reddish brown colour of
Observation Reddish brown colour of bromine is remain unchanged
bromine disappeared

Equation CH3 CH3
CH3C CHCH3 Br2, CH2Cl2 CH3C CHCH3

Br Br

8. W and X are isomers.
C:H:O ratio suggests that W and X are aromatic compounds with carbonyl group.
Fehling’s test shows that W can be oxidised while X cannot. Therefore W is an aldehyde
while X is a ketone.
W: O

CH2CH

X: O
C CH3

Reduction of X produces alcohol Y
Y: OH

CHCH3

Positive iodoform test proves that X has methyl carbonyl group while Y has methyl carbinol
group
(a)

CH2CH2OH

(b)

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COOH

MEKA 3-methylpentanal
1. (a) 3-pentenal
2-chloro-5-methylcyclopentanone
(b)
(c)

2. (a) (c)
O

H3C

O CH3

(b) (d) CH3
O O
CH3
H H3C CH
H3C
NO2
Cl

3. (a)

Test Fehling test

Reagent & Reagent: Cu2+ complex, OH-

Conditions

Compound pentanal 2-pentanone

Observation Brick-red precipitate formed. Does not form brick-red
precipitate.

Equation CH3 CH2 CH2 CH2 C Cu2+ complex, NaOH(aq) CH3 CH2 CH2 CH2 C +O- Cu2O
O H

O

(b)

Test Iodoform test:

Reagent & Excess I2, NaOH
Conditions

Compound ethanal propanal
No light yellow precipitate
Observation Light yellow precipitate formed.
formed.

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CHAPTER 16: CARBONYL COMPOUNDS

excess I2, NaOH(aq) +-

Equation H3C C H HCO CHI3
O
O

4. (a)

HBr, ROOR Br Mg, ether MgBr

H3C CH2 H3C H3C

i) CH3CH2COH, ether
ii) H3O+

O OH

H3C CH3 KMnO4, H+ H3C CH3


(b)

conc. H2SO4 CH2 H2, Pt CH3

H3C OH H3C H3C



5. OH O
O H3C A CH3
H2O H3C CH3 
H3C A CH3 B
HBr

Br KOH, Ethanol D

H3C CH2

H3C C CH3 reflux

KMnO4, H+,

+ +H3C COOH CO2 H2O

6. E: H: K:
OH OH
NNH2
CH3 CHCH2CH2 CH3 CHCH2CCH2 CH3
CH3 CHCH2CH CH3 CH3 H

CH3 I: L:
F:

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CHAPTER 16: CARBONYL COMPOUNDS

OH O OH
CH3 CHCH2CH2
CH3 CHCH2CH CH3 CHCH2C OH
CH3 CN CH3 CH3

G: J:
O OCH2CH3

CH3 CHCH2C OH CH3 CHCH2C OCH2CH3
CH3 CH3 H

KUMBE 2,2-dimethylpropanal
1. (a) 3-bromobutanal
4-hydroxycyclohexanone
(b) 3-pentenal
(c)
(d)

2. (a)

OH + O
CH3CH2CH2C CH3
KMnO4,H3O ,heat

CH3CH2CH2CHCH3

(b)

CH3 CH2CH2Cl NaCN, H3O+ CH3 CH2CH2CN H3O+ CH3 CH2CH2COOH

i)LiAlH4
ii)H3O+

CH3 CH2CH2 CHO PCC, CH2Cl2
CH3 CH2CH2 CH2 OH

(c)

i. LiAlH4, ether conc. H2SO4

CH3 CH2 CH2 CHO ii. H3O+ CH3 CH2 CH2 CH2 OH CH3 CH2 CH CH2
H3O+

CH3 CH CH CH3 conc. H2SO4
 CH3 CH2 CHCH3
OH

3. (a) P: Hydroxyl
Q: Carbonyl

(b)
Test Brady test
Reagent & 2,4-dinitrophenylhydrazine
Conditions

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CHAPTER 16: CARBONYL COMPOUNDS

O

Compound

Orange precipitate does not Orange precipitate is formed.
Observation

formed.

O

Equation + H2NHN NO2 NHN NO2
NO2
NO2

(c) O
OH

KMnO4,H+


4. R: U:

H3C CH3 H3C CH3

OH O

S: V:

H3C CH3

H3C CH3 N
HO

T:

H3C CH

O

5. NaOH(aq) CH
W O
CH2 CH2
Br OH Y

X KMnO , H+

4 O2N NHNH2



COOH H NO2
C CH2NHN NO2
Z

O2N

Orange precipitate

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