2. IUPAC NOMENCLATURE
- From name to structure (quite frequent in questions)
- From structure to name
- emerging trend (follow the rules exactly)
2
2-methyl-2-propanol or 2-methylpropan-2-ol
C
H
3
C
H
3
C
O
H
C
H
3
Ethyl ethanoate space
2-bromo-1-chloropentane alphabetical, no space
2,3-dimethyl-1-pentene commas, dash
What about
Toluene, phenol, aniline, benzoic acid, benzaldehyde?
3. 3
CH3CH2NH2 + Br2 CH2BrCH2NH2 + HBr
CH3CH2NH2 + Br2 CH3CHBrNH2 + HBr
or
UV light or heat ≥ 400 oC
NH2
+ Br2
NH2
Br
Br
Br
Electrophilic substitution
NOT LIGHT or SUNLIGHT or HEAT
NOT Electrophilic
NOT Substitution
Example (STPM 2014)
Both ethylamine and phenylamine react with bromine under different
reaction conditions.
Write an equation for the reaction of phenylamine with bromine,
and name the type of reaction that is involved.
[2 marks]
Write an equation for the reaction of ethylamine with bromine,
and give the reaction condition involved.
[2 marks]
4. 4
Mistakes by many candidates
Both ethylamine and phenylamine react with bromine under different
reaction conditions.
UV light or heat ≥ 400 oC
Electrophilic substitution
wrote HBr instead of Br2
How many marks?
Write an equation for the reaction of phenylamine with bromine, and
name the type of reaction that is involved.
[2 marks]
Write an equation for the reaction of ethylamine with bromine, and give
the reaction condition involved.
[2 marks]
NH2
+ HBr
NH3Br
C
H
3
C
H
2
N
H
2
+
H
B
r C
H
3
C
H
2
N
H
3
B
r
5. 5
Example (STPM2014)
Draw the structure of the repeating unit of the polymer obtained from
the following monomer, and state the type of polymerisation involved.
Monomer: CH2=CHF [2 marks]
C
H
C
H H
F
√
√
Addition polymerisation
NOT
Additional polymerisation
C
H
C
H
H
F
n
N
O
T
6. Writing correctly reaction equations…
6
(STPM 2009)
Compound Y reacts with a hot acidified solution of potassium
manganate(VII). Write the equation for the reaction.
C
H3C
OH
H
CH2CH3
KMnO4/H+
C
H3C CH2CH3
O
C
H3C
OH
H
CH2CH3
C
H3C CH2CH3
O
[O]
C
H3C
OH
H
CH2CH3
C
H3C CH2CH3
O
potassium manganate(VII)
X
X
7. 7
The structural formula of an organic compound is as follows:
HO CH2CHCH3
OH
Draw the structural formula of the organic product(s) formed when the
compound reacts with each of the following reagents:
•Sodium metal
•An aqueous solution of sodium hydroxide
•An alkaline iodine solution
•A hot acidic potassium manganate(VII) solution
NaO CH2CHCH3
ONa
NaO CH2CHCH3
OH
NaO CH2COONa + CHI3
HO COOH
N
a
O
C
H
2
C
H
C
H
3
O
H
H
O
C
H
2
C
O
O
H
+
C
H
3
I
H
O
C
H
2
C
C
H
3
O
9. Compounds X and Y are
carbonyl compounds with
molecular formula, C8H8O.
Y does not react with hot
solution of acidified
potassium manganate(VII),
whereas X reacts to give
compound Z. Z can be
prepared from
(chloromethyl)benzene
Deduce the structural
formulae of X, Y and Z.
[5 marks]
CH2CHO CHO
CH3
or
COCH3
COOH COOH
COOH
or
X is an aldehyde
Y is a ketone
(depending on X)
Z
(or m- or p-)
10. 10
Give appropriate chemical tests, with observations, to confirm the
proposed structures of X and Y. Write all the equations for the
reactions involved.
CH2CHO CH2COO- + Ag
+ Ag+
CH2CHO CH2COO- + Cu+ (or Cu2O)
+ Cu2+
or
COCH3 + I2/NaOH COONa + CHI3
For X, Tollens’ test or silver mirror test / Fehling test or Benedict test
Metallic silver or silver mirror / brick-red precipitate
For Y, iodoform test
Yellow precipitate
√
√
√
√
√
√
11. Compounds X and Y are carbonyl compounds with
molecular formula, C8H8O. Y does not react with hot solution
of acidified potassium manganate(VII), whereas X reacts to
give compound Z. Z can be prepared from
(chloromethyl)benzene
Show how Z can be prepared from (chloromethyl)benzene.
[4 marks]
CH2Cl
NaOH
CH2OH
KMnO4
COOH
H+
COOH
COOH
√
√
what if your Z is ?
√
√
√
13. Chemical Test
13
Choose a simple reagent
State the conditions (acidic/heat/solvent)
Results are observable (colour change,
precipitate, bubbles)
If to distinguish two compounds, must state
observations for both reactions, cannot write
“NO REACTION”; write “NO OBSERVABLE
CHANGE”
Write an equation for positive test
15. 15
Give appropriate chemical tests, with observations, to confirm the
proposed structures of X and Y. Write all the equations for the reactions
involved.
CH2CHO CH2COO- + Ag
+ Ag+
CH2CHO CH2COO- + Cu+ (or Cu2O)
+ Cu2+
or
Use Tollens’ test or silver mirror test / Fehling test or Benedict test
Metallic silver or silver mirror / brick-red precipitate for X
Y does not react
√
√
Lost 3 marks
Most candidates assumed a chemical test to distinguish
X and Y
16. Another example
16
(STPM 2009)
Describe chemical tests which could be performed on dopamine to
confirm the presence of phenolic and amino groups in it. Write
equations for the reaction involved.
OH
OH
CH2CH2NH2
Acceptable: FeCl3 or Br2(aq) (for phenolic)
: HNO2/< 10oC (for amino)
Unacceptable: NaOH (for phenolic)
: HCl (for amino)
why?
17. 17
Starting with 1-bromopropane, show the reaction scheme to
synthesize (a) CH3CH2COOH, (b) CH3CH2CH2COOH
(4 marks)
NaOH(aq) KMnO4/H+
CN-
H2O/H+
CH3CH2CH2Br CH3CH2CH2OH CH3CH2COOH
CH3CH2CH2CN CH3CH2CH2COOH
[4 mark
18. 18
Common mistakes
(How many?)
[4 mark
K M n O 4 / H +
H C N
H 2 O / H +
C H 3 C H 2 C H 2 B r C H 3 C H 2 C H 2 O H C H 3 C H 2 C O O H
C H 3 C H 2 C H 2 C N C H 3 C H 2 C H 2 C O O H
N a O H
K
M
n
O
4
/H
+
K
C
N
H
2
O
/H
+
C
H
3
C
H
2
B
r C
H
3
C
H
2
O
H C
H
3
C
H
2
C
O
O
H
C
H
3
C
H
2
C
N C
H
3
C
H
2
C
H
2
C
O
O
H
N
a
O
H
(
a
q
)
19. 19
Aspirin has the following structure:
OH
O C
O
CH3
Give the products formed when aspirin is heated with aqueous potassium
hydroxide solution. [2 marks]
OK
OK
CH3COOK
and
O K
O C
O
C H 3
O
N
a
O
N
a
C
H
3
C
O
O
N
a
a
n
d
O
-
O
-
C
H
3
C
O
O
-
a
n
d
20. 20
3-Methyl-4-
hexen-3-ol
shows
stereoisom
erism
which is
geometrical
and optical
isomerism.
Describe
the
stereoisom
erism
present in
this
compound.
[8 marks]
CH2CH3
C
C
C
H3C
OH
CH3
H
H
Geometrical isomerism
There a two different groups bonded to the same carbon with the double bond
CH2CH3
C
C
C
H3C
OH
H3C
H H
cis
CH2CH3
C
C
C
H3C
OH
H3C
H
H
trans
Optical isomerism
A chiral carbon/four different groups bonded to the same carbon
Non-superimposable mirror image
CH2CH3
CH=CHCH3
H3C H
CH2CH3
CH=CHCH3
H CH3
Stereoisomerism - the existence of two or more compounds having the same chemical and structural
formula but differ in the arrangment of atoms or groups in space
or CH3CH=CHC(CH3)(OH)CH2CH3
NOT CH3CHCHC(CH3)(OH)CH2CH3
21. 21
Other Mistakes
Geometrical - two different groups bonded to the same carbon
CH2CH3
C
C
C
H3C
OH
CH3
H H
cis trans
Optical isomerism - chiral carbon/four different groups bonded to the same carbon
CH2CH3
CH=CHCH3
H3C H
CH2CH3
CH=CHCH3
H C3H
Did not define stereoisomerism
Incorrect /incomplete definition
Stereoisomerism - same chemical and structural formula but differ in the arrangment of atoms or
groups
Incorrect structure
Did not label cis/trans or incorrectly labelled
CH2CH3
C
C
C
H3C
OH
CH3
H
H
22. Propene polymerises in the presence of benzoyl peroxide, C6H5COO-OOCC6H5, to form
polypropene. Explain, with chemical equations, the reactions which occur in the
polymerisation of propene. [7 marks]
22
C C
H
CH3
H
H
n
free-radical addition polymerisation
C6H5COO-OOCC6H5 2 C6H5COO
initiation
propagation
H2C C
H
CH3
H2C C
H
CH3
C6H5COO + CH
CH3
C6H5COO-CH2
CH
CH3
C6H5COO-CH2 H2C C
H
CH3
+ CH-CH2-CH
CH3
C6H5COO-CH2
CH3
termination
C6H5COO-OOCC6H5
2 C6H5COO
CH
CH3
C6H5COO-CH2
2
CH3
C6H5COOCH2CH CHCH2OOCC6H5
CH3
23. For free-radical reactions
Must show ‘dot’ for free radicals
Must write:
Initiation step
Propagation step (at least two steps)
Termination step
23
24. 24
Z i s C H 3 C H C l C H 2 C H 3
e l i m i n a t i o n r e a c t i o n / d e h y d r o h a l o g e n a t i o n r e a c t i o n
p r o d u c t s :
C H 2 = C H C H 2 C H 3
C
C
C H 3
H
H
H 3 C
C
C
C H 3
H
H
H 3 C
c i s t r a n s
An optically active compound Z, with molecular formula
C4H9Cl, reacts with ethanolic potassium hydroxide solution to
form three isomers of unsaturated organic compounds.
Write the structural formula of Z, and explain its reaction with
ethanolic potassium hydroxide solution. [5 marks]
25. Some mistakes
25
C
H
2
C
H
C
H
2
C
H
3
C
C C
H
3
H
H
H
3
C C
C C
H
3
H
H
H
3
C
c
i
s t
r
a
n
s
B
i
m
o
l
e
c
u
l
a
r
n
u
c
l
e
o
p
h
i
l
i
c
s
u
b
s
t
i
t
u
t
i
o
n
/
S
N
2
C
H
3
C
H
(
O
H
)
C
H
2
C
H
3
C
H
2
C
H
3
H
O
C
H
3
H
C
H
2
C
H
3
H
C
H
3
O
H
26. An optically active compound Z, with molecular formula C4H9Cl, reacts with ethanolic potassium
hydroxide solution to form three isomers of unsaturated organic compounds.
(a) Write the structural formula of Z, and explain its reaction with ethanolic potassium hydroxide
solution.
(b) Determine the isomer of Z which reacts with ethanolic potassium hydroxide solution to form
only one organic compound. Give a reason for your answer. [3 marks]
26
C
CH3
H3C Cl
CH3
C CH3
CH3
H2C
All H atoms are equivalent
KOH
ethanol
C
C
l
C
H
3
C
H
3
C
H
3
What is wrong with these?
CH2C(CH3)2
27. Reaction mechanism
(STPM 2009)
Give an example of an addition reaction involving bromine, and
describe the mechanism involved.
[4 marks]
Errors:
Use HBr or Cl2
instead of Br2
Direction of
arrows
27
H2C CH2 + Br2 CH2BrCH2Br
C C
H
H H
H
d+ d- C
C
Br
+
+ Br-
H
H
H
H
C
C
Br
H
H
H
H
+
Br-
C
Br
H C
H
H
Br
H
trans attack
Br Br
28. Detect the errors
(STPM 2009)
Give an example of addition reaction involving bromine, and describe
the mechanism involved.
[4 marks]
How many marks?
28
H2C CH2 + Br2 CH2BrCH2Br
C C
H
H H
H
C
C
Br
+
+ Br-
H
H
H
H
C
C
Br
H
H
H
H
+
Br-
C
Br
H C
H H
Br
H
Br Br
29. Carelessness
(STPM 2009)
Give an example of addition reaction involving bromine, and
describe the mechanism involved.
[4 marks]
29
X
H2C CH2 + HBr CH3CH2Br
C C
H
H H
H
C
C
+
+ Br-
H
H
H
H
Br-
C
Br
H C
H H
H
H
H Br
H
C
C
+
H
H
H
H
H
H+
+ Br-
H+
30. Emerging trend
Multiple-steps organic synthesis
(STPM 2005)
By giving reagents and reaction
conditions, show the synthesis
of M from 2-nitrotoluene.
30
CH3
NO2
KMnO4/H+
COOH
NO2
Sn/HCl
COOH
NH2
Why cannot use LiAlH4?
CO2H
NH2
M
31. 2013
Show how 2-hydroxybenzamide can be synthesised using
phenol as the starting material. [9 marks]
31
Things to remember
Show all steps
Correct formula for reagents
Correct conditions
Correct sequence
