71

Phenols WS 1
PHENOLS
14 WS 1

1 7 (a) (i) State and explain the relative acidities of ethanol and phenol.

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) In the table below, give the reaction conditions for the formation of organic products D and
E and draw their structures.

OH

HNO3 Br2
D E

phenol

reagent conditions structure

D

HNO3 dilute, 5 C

Br2

[3]

(iii) Name the mechanism of the reaction forming compound E.

....................................................................................................................................... [1]

[M'16 P42 Q7]

(b) (i) Phenylamine reacts with aqueous bromine to give compound F.

Describe the appearance of compound F.

....................................................................................................................................... [1]

(ii) Phenylamine reacts with nitrous acid to form a diazonium salt.

State the conditions for this reaction.

....................................................................................................................................... [1]

© UCLES 2016 9701/42/F/M/16

Phenols 1
 72
10

62 Oleocanthal, Q, is a natural compound found in olive oil. It has antioxidant and anti-inflammatory
properties and is thought to have a protective effect against Alzheimer’s disease.

O
HO
O
Q

(a) Q shows optical and cis-trans isomerism.

On the structure of Q above, circle the functional group that shows cis-trans isomerism and
indicate with an asterisk (*) the chiral carbon atom. [1]

(b) Q can be isolated from olive oil by partitioning between two solvents.

(i) Explain what is meant by the term partition coefficient.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) When 40.0 cm3 of hexane was shaken with 10.0 cm3 of a solution containing 0.25 g of Q in
10.0 cm3 of methanol, it was found that 0.060 g of Q was extracted into the hexane.

Calculate the partition coefficient, Kpartition, of Q between hexane and methanol.

Kpartition = ............................. [2]

© UCLES 2016 9701/42/O/N/16

 73
11

(c) Complete the following table to show the structures of the products formed when Q reacts with
the three reagents.

reagent structure of product(s) type of reaction

excess
Br2(aq)

NaBH4

excess hot
NaOH(aq)

[6]

(d) When a sample of Q synthesised in a laboratory was compared to a natural sample from olive
oil, it was found that the therapeutic activity of the synthetic sample was lower.

Suggest a reason for this.

....................................................................................................................................................

.............................................................................................................................................. [1]

[Total:
[N’16 P4212]
Q6]

© UCLES 2016 9701/42/O/N/16 [Turn over

Phenols 1
 74
11

3 (c) Phenol can be used to make 2-nitrophenol.

OH

NO2
2-nitrophenol

The nitration reaction of phenol to form 2-nitrophenol shows that phenol is more reactive than
benzene.

(i) Describe the conditions used for the nitration of phenol.

Explain how these conditions show phenol to be more reactive than benzene.

conditions ...........................................................................................................................

explanation .........................................................................................................................

.............................................................................................................................................

.............................................................................................................................................
[2]

(ii) Suggest why phenol is more reactive than benzene.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [1]

(iii) Complete the mechanism for the nitration of phenol to form 2-nitrophenol. You should
assume that the mechanism is the same as that for the nitration of benzene.

OH
+
NO2
products

phenol intermediate
[3]

(iv) Name the isomer of 2-nitrophenol which is also a major product of this reaction.

....................................................................................................................................... [1]

[Total:
[J’18 P4214]
Q6]

© UCLES 2018 9701/42/M/J/18 [Turn over

Phenols 1
 75
16

74 (a) Chlorobenzene and phenol both show a lack of reactivity towards reactants that cause the
breaking of the C–X bond (X = Cl or OH).

Explain why.

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [3]

(b) When phenol is reacted with bromine dissolved in an inert solvent, two isomeric bromophenols,
C6H4BrOH, are formed.

Suggest structures for these products. Name each compound.

name: ..................................................................

name: ..................................................................
[2]

[N’18 P41 Q7]

© UCLES 2018 9701/41/O/N/18

Phenols 1
 76

Phenols10 WS 2
14 Cyclohexanol and phenol are both solids with low melting points that are fairly soluble in For
water. Examiner’s
Use

OH OH

cyclohexanol phenol

(a) Explain why these compounds are more soluble in water than their parent hydrocarbons
cyclohexane and benzene.

..........................................................................................................................................

..........................................................................................................................................

..................................................................................................................................... [2]

(b) Explain why phenol is more acidic than cyclohexanol.

..........................................................................................................................................

..........................................................................................................................................

..................................................................................................................................... [2]

Phenols 2

© UCLES 2009 9701/41/O/N/09

 7711

(c) For each of the following reagents, draw the structural formula of the product obtained For
for each of the two compounds. If no reaction occurs write no reaction in the box. Examiner’s
Use

reagent product with cyclohexanol product with phenol

Na(s)

NaOH(aq)

Br2(aq)

I2(aq) + OH–(aq)

an excess of
acidified Cr2O 27 –(aq)

[7]

(d) Choose one of the above five reagents that could be used to distinguish between
cyclohexanol and phenol. Describe the observations you would make with each compound.

reagent ........................................................................................

observation with cyclohexanol ........................................................................................

observation with phenol ........................................................................................

[2]
[N'09 P41 Q4]
[Total: 13]

© UCLES 2009 9701/41/O/N/09 [Turn over

Phenols 2
 78
5
23 Menthol and menthone, the main constituents of oil of peppermint, can be made synthetically For
from thymol by the following route. Examiner’s
Use

I II

OH OH O

thymol menthol menthone

(a) State the type of reaction of

• reaction I, ..........................................................................................................

• reaction II. .........................................................................................................

[2]

(b) Suggest one test for each of the three compounds that would give a positive result with
the stated compound but a negative result with both the other two compounds.

thymol

test ...................................................................................................................................

observation ......................................................................................................................

menthol

test ...................................................................................................................................

observation ......................................................................................................................

menthone

test ...................................................................................................................................

observation .................................................................................................................. [6]

[N'10 P43 Q3]
[Total: 8]

© UCLES 2010 9701/43/O/N/10 [Turn over

Phenols 2
 79 8 For
Examiner’s
Use
34 Ethyl 4-hydroxybenzoate, E, is a permitted food preservative.

HO CO2C2H5

(a) Name two functional groups in E.

..........................................................................................................................................

......................................................................................................................................[2]

(b) Draw the structures of the compounds formed when E reacts with

(i) sodium metal,

(ii) NaOH(aq) under reflux,

(iii) Br2(aq).

[4]

9701/4/O/N/03

Phenols 2
 80 9 For
Examiner’s
Use
(c) Compounds F and G are isomers of E.

HOCH2 CO2CH3 CH3CH2O CO2H

F G

(i) Suggest the order of acid strength of E, F and G.

...................................................................................................................................

...................................................................................................................................

(ii) Based on their relative acidities, suggest how samples of E, F and G could be
distinguished from each other by the use of NaOH(aq) and Na2CO3(aq).

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................

...................................................................................................................................
[3]
[N'03 P4 Q4]
[Total : 9]

9701/4/O/N/03 [Turn over

Phenols 2
 81 For
10
Examiner’s
Use
46 Chemists use skeletal or partial-skeletal formulae to represent larger structures. For example
the structure

CH3 OH
CH2 H
C
H2C C
CH2
H2C CH
CH2
CH2

may also be represented as follows.

OH
CH3 H

Oestradiol is one of the hormones that controls the reproductive cycle in female mammals.

HO
CH3 H

H
H H

HO
oestradiol

(a) (i) On the above structure of oestradiol, circle one chiral centre.

(ii) What is the total number of chiral centres in the oestradiol molecule? .....................
[2]

(b) Complete the following part-structures (which have the -OH groups removed) to show
the products obtained when oestradiol (above) is reacted with the stated reagents.

(i) sodium metal

CH3

H
H H

© UCLES 2007 9701/04/M/J/07

Phenols 2
 82 For
11
Examiner’s
Use
(ii) Br2(aq)

CH3

H
H H

(iii) NaOH(aq)

CH3

H
H H

(iv) CH3COCl

CH3

H
H H

(v) hot acidified K2Cr2O7

CH3

H
H H

[7]
[J'07 P4 Q6]
[Total: 9]

© UCLES22007
Phenols 9701/04/M/J/07 [Turn over
 83
10

55 (a) A series of experiments is carried out in which the reagent shown at the top of the column
For
Examiner’s
of the table is mixed, in turn, with each of the reagents at the side. Use
Complete the following table by writing in each box the formula of any gas produced.
Write x in the box if no gas is produced.
The first column has been completed as an illustration.

OH CO2H OH

H 2O

Na H2
KOH(aq) x
Na2CO3(aq) x

[5]

(b) Compound C is responsible for the pleasant aroma of apples. It can be prepared from
phenol by the following 3-step synthesis.

OH OH OH O CH3
step step step
1 2 3

C C C
H 3C CH3 H 3C CH3 H 3C CH3
CH3 CH3 CH3

A B C

(i) The only by-product of step 1 is HCl. Suggest the reagent that was used to react
with phenol to produce compound A.

....................................................................................................................................

(ii) What type of reaction is occurring in step 2?

....................................................................................................................................

(iii) What reagents and conditions are required for step 3?

....................................................................................................................................

(iv) State the reagent and conditions needed to convert C back to B, the reverse of
step 3.

....................................................................................................................................
[5]

© UCLES 2013 9701/41/M/J/13

Phenols 2
 84
11
For
(c) (i) Either compound A or compound B, or both, react with the following reagents. Examiner’s
For each reagent draw the structure of the organic product formed with A, and with Use
B. If no reaction occurs, write ‘no reaction’ in the relevant box.

reagent and conditions product with A product with B

an excess of Br2(aq)

heat with HBr

pass vapour over

heated Al 2O3

heat with acidified K2Cr2O7

(ii) Choose one of the above reactions to enable you to distinguish between A and B.

State below the observations you would make with each compound.

reagent observation with A observation with B

[7]
[J'13 P41 Q5]
[Total: 17]

© UCLES 2013 9701/41/M/J/13 [Turn over

Phenols 2
 985

65 Coffee beans contain chlorogenic acid.

For
Examiner’s
Use
OH

O O OH
OH
O

HO OH
HO

chlorogenic acid

(a) (i) Draw circles around any chiral centres in the above structure.

(ii) Write down the molecular formula of chlorogenic acid.

....................................................................................................................................

(iii) How many moles of H2(g) will be evolved when 1 mol of chlorogenic acid reacts with
an excess of sodium metal?

....................................................................................................................................

(iv) How many moles of NaOH(aq) will react with 1 mol of chlorogenic acid under each
of the following conditions?

in the cold ...............................................

on heating ...............................................
[6]

© UCLES 2013 9701/42/M/J/13 [Turn over

Phenols 2
 86
10
For
(b) On heating with dilute aqueous acid, chlorogenic acid produces two compounds, D and Examiner’s
E. Use

OH
OH OH
O
dil. H+(aq) +
chlorogenic acid
heat HO O OH
HO OH
HO
D E
conc.
H2SO4 Br2(aq)
heat in excess

C7H6O3
F G

(i) What type of reaction is chlorogenic acid undergoing when D and E are formed?

....................................................................................................................................

When compound D is heated with concentrated H2SO4, compound F, C7H6O3, is formed.

Compound F evolves CO2(g) when treated with Na2CO3(aq), and decolourises Br2(aq),
giving a white precipitate. It does not, however, decolourise cold dilute acidified KMnO4.

When compound E is treated with an excess of Br2(aq), compound G is produced.

(ii) If the test with cold dilute acidified KMnO4 had been positive, which functional group
would this have shown to be present in F?

....................................................................................................................................

(iii) Name the functional groups in compound F that would react with the following.

Na2CO3(aq) ................................................. Br2(aq) .................................................

(iv) Suggest structures for compounds F and G and draw them in the relevant boxes
above.

© UCLES 2013 9701/42/M/J/13

Phenols 2
 7
87
11
For
(d) Propanoic acid, CH3CH2CO2H, is a weak acid with Ka = 1.34 10–5 mol dm–3. Examiner’s
For
7
(v) Compound E is one of a pair of stereoisomers. Use
Examiner’s
(i) Calculate the pH of a 0.500 mol dm–3 solution of propanoic acid. –5 Use
For
(d) Propanoic
What typeacid, CH3CH2CO2H, isisa shown
of stereoisomerism weak acid with Ka = 1.34
by compound E? 10 mol dm .
–3
Examiner’s
Use
(i) Calculate the pH of a 0.500 mol dm–3 solution of propanoic acid.
....................................................................................................................................

(vi) Draw the structure of the other stereoisomer in the box below.

Buffer solution F was prepared by adding 0.0300 mol of sodium hydroxide to 100 cm3 of
a 0.500 mol dm–3 solution of propanoic acid.
Buffer solution F was prepared by adding 0.0300 mol of sodium hydroxide to 100 cm3 of
(ii) Write an equation
a 0.500 mol dm–3for the reaction
solution between
of propanoic sodium hydroxide and propanoic acid.
acid.

(ii) Write an equation for the reaction between sodium hydroxide and propanoic acid.
....................................................................................................................................

....................................................................................................................................
(iii) Calculate the concentrations of propanoic acid and sodium propanoate in buffer
solution F.
(iii) Calculate the concentrations of propanoic acid and sodium propanoate in buffer
solution F.

[propanoic acid] = ................................ mol dm–3

[8]
[propanoic acid] = ................................ mol dm–3
(c) Calculate the volume of 0.1 mol dm–3 NaOH that is needed to react completely with 0.1 g
of compound E. [sodium propanoate] = ................................ mol dm–3
[sodium propanoate] = ................................ mol dm–3
(iv) Calculate the pH of buffer solution F.
(iv) Calculate the pH of buffer solution F.

volume = ....................... cm3

pH = ................................ [3]
pH = ................................
[6]
[J'13 P42 Q5]
[Total: 17] [6]
7(e) Phenyl propanoate cannot be made directly from propanoic acid and phenol.
(e) Phenyl
Suggest propanoate
the identities cannot
of the be made G,
intermediate directly from propanoic
the reagent acidby-product
H and the and phenol.J in the
Suggest the identities
following reaction scheme. of the intermediate G, the reagent H and the by-product J in the
following reaction scheme.
ONa
ONa

H O O
H
CH3CH2CH
CO2CH
H CO H G G + +J J
3 2 2
O O

G is ..........................................................
G is ..........................................................

H is ..........................................................
H is ..........................................................

J is ..........................................................
J is ..........................................................
[2] [2]
[N'13 P41 Q3]
[Total:
[Total: 18] 18]

© UCLES 20132013
© UCLES 9701/42/M/J/13
9701/41/O/N/13 [Turn
[Turn over
over
© UCLES 2013 9701/41/O/N/13 [Turn over
Phenols 2
 888
For
85 (a) Bromine reacts with a variety of organic compounds. Examiner’s
For each of the following reactions, Use

complete and balance the equation, including the structural formula of the organic
product,

state the specific conditions (if any) under which the reaction takes place and the
type of reaction that occurs.

OH

(i) ............Br2 +

reaction conditions .....................................................................................................

type of reaction ..........................................................................................................

(ii) ............Br2 +

reaction conditions .....................................................................................................

type of reaction ..........................................................................................................

(iii) ............Br2 +

reaction conditions .....................................................................................................

type of reaction ..........................................................................................................

[10]

© UCLES 2013 9701/43/O/N/13

Phenols 2
 989
For
(b) When hydrocarbon B is heated with concentrated manganate(VII) ions, three organic Examiner’s
compounds, C, D and E, are formed. Use

hot MnO4–

D
B

(i) Suggest the identities of compounds C, D and E, drawing their structures in the
boxes above.

(ii) Use the relevant letter, C, D or E, to identify which of your compounds will react with
each of the following reagents.
Each reagent may react with more than one of C, D and E, in which case state all
the compounds that may react with each reagent.

2,4-dinitrophenylhydrazine ..............................

alkaline aqueous iodine ...................................

aqueous sodium hydroxide ..............................

[6]
[N'13 P43 Q5]
[Total: 16]

© UCLES 2013 9701/43/O/N/13 [Turn over

Phenols 2
 9010
10
95 (a) Describe and explain how the acidities of ethanol and phenol compare to that of water. For
5 (a) Describe and explain how the acidities of ethanol and phenol compare to that of water. Examiner’s
For
.......................................................................................................................................... Use
Examiner’s
.......................................................................................................................................... Use

..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
......................................................................................................................................
......................................................................................................................................[4]
[4]

(b) (b)
Complete the the
Complete following equations
following showing
equations showing allall
the products
the productsofofeach
eachofofthese
thesereactions
reactions of
of
phenol.
phenol. Include reaction conditions where appropriate in the boxes over the arrows.IfIf no
Include reaction conditions where appropriate in the boxes over the arrows. no
reaction occurs
reaction write
occurs no no
write reaction in in
reaction thethe
products
products box.
box.

OH OH

+ Na
+ Na

OH OH

+ NaOH
+ NaOH

OH
OH

+ CH3CO2H
+ CH3CO2H

OH
OH

+ Br2
+ Br2

[5]
[5]Q5]
[J'11 P42

© UCLES 2011 9701/42/M/J/11

© UCLES 2011 9701/42/M/J/11

Phenols 2
 91
10

10
5 L-DOPA is used in the treatment of Parkinson's disease. It can be prepared from vanillin.

HO HO
NH2
H
HO CO2H CH3O
O
L-DOPA vanillin

(a) L-DOPA and vanillin each contain an aromatic benzene ring.

Describe, with the aid of a diagram, the bonding and shape of a molecule of benzene, C6H6.

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

....................................................................................................................................................

.............................................................................................................................................. [5]

© UCLES 2014 9701/43/O/N/14

Phenols 2
 92
11

(b) A student carried out some reactions with samples of L-DOPA and vanillin using reagents X, Y
and Z.

Reagent X reacted with L-DOPA and with vanillin.

Reagent Y reacted with L-DOPA but not with vanillin.
Reagent Z reacted with vanillin but not with L-DOPA.

Assume that the CH3O– group in vanillin does not react.

Suggest possible identities of reagents X, Y and Z and give the structures of the organic
products that were formed.

Reagent X ..................................................................................................................................

product with L-DOPA product with vanillin

Reagent Y ..................................................................................................................................

product with L-DOPA

Reagent Z ..................................................................................................................................

product with vanillin

[7]
[N'14 P43 Q5]
[Total: 12]

© UCLES 2014 9701/43/O/N/14 [Turn over

Phenols 2
 93
10

126 Oleocanthal, Q, is a natural compound found in olive oil. It has antioxidant and anti-inflammatory
properties and is thought to have a protective effect against Alzheimer’s disease.

O
HO
O
Q

(a) Q shows optical and cis-trans isomerism.

On the structure of Q above, circle the functional group that shows cis-trans isomerism and
indicate with an asterisk (*) the chiral carbon atom. [1]

(b) Q can be isolated from olive oil by partitioning between two solvents.

(i) Explain what is meant by the term partition coefficient.

.............................................................................................................................................

.............................................................................................................................................

....................................................................................................................................... [2]

(ii) When 40.0 cm3 of hexane was shaken with 10.0 cm3 of a solution containing 0.25 g of Q in
10.0 cm3 of methanol, it was found that 0.060 g of Q was extracted into the hexane.

Calculate the partition coefficient, Kpartition, of Q between hexane and methanol.

Kpartition = ............................. [2]

© UCLES 2016 9701/42/O/N/16

Phenols 2
 94
11

(c) Complete the following table to show the structures of the products formed when Q reacts with
the three reagents.

reagent structure of product(s) type of reaction

excess
Br2(aq)

NaBH4

excess hot
NaOH(aq)

[6]

(d) When a sample of Q synthesised in a laboratory was compared to a natural sample from olive
oil, it was found that the therapeutic activity of the synthetic sample was lower.

Suggest a reason for this.

....................................................................................................................................................

.............................................................................................................................................. [1]

[N'1612]
[Total: P42 Q6]

© UCLES 2016 9701/42/O/N/16 [Turn over

Phenols 2