EXTRA ALIPHATIC ORGANIC QUESTIONS – MARK SCHEME
SECTION A – MULTIPLE CHOICE
1.
D
2.
C
3.
B
4.
B
5.
B
6.
D
7.
C
8.
D
9.
B
10.
A
11.
D
12.
B
13.
B
14.
B
SECTION B – SHORT ANSWERS
15.
(a)
(i)
Initiation (1)
Cl2  2Cl (1)
Propagation (1)
e.g CH4 + Cl  CH3 + HCl (1)
Termination (1)
e.g CH3 + Cl  CH3Cl (1)
(ii)
(b)
to minimize further substitution (1)
nucleophilic
substitution (1)
(1)
CH 3 CH 2
Br
CH 3 CH 2 OH
(1)
(1)
H –
(c)
sodium salt of long chain carboxylic acid (1)
CH 2
CH
CH 2
(1)
OH
OH
OH
2
[13]
Mill Hill High School
1
16.
(a)
(i)
methyl ethanoate (1)
(ii)
CH3COOCH3 + H2O  CH3COOH + CH3OH (1)
(iii)
Catalyst (1)
3
(b)
solvents/plasticizers (1)
(c)
(i)
(ii)
Line with the highest m/z (1)
1
O
R
C
OC4 H 9
101
R = 116 – 101 = 15
CH3COOC4H9 (1)
Molecular formula = C6H12O2 (1)
3
[7]
17.
(a)
(i)
O
CH 3
CH
CH 2 CH 3 + CH 3 COOH
CH 3
C
CH 3
O
OH
+ H2O
CH
CH 2 CH 3
eqn (1)
(1)
(ii)
ester (1)
solvent, flavourings (1)
(iii)
conc
H2SO4 (1)
in same physical state (1)
6
(b)
C4H10O + 6O2  4CO2 + 5H2O (1)
1
(c)
(i)
CH 3
CH
CH 2 CH 3
CH 3
OH
(1)
CH
CH 2 CH 3
CH 2
H (1)
+ OH 2
+
CH
CH 2 CH 3
(1)
(1)
H+
CH 2 = CHCH 2 CH 3
(ii)
two H on carbon in double bond (1)
(iii)
CH 3
CH 3
C
H
(1) or
C
H
cis but-2-ene (1)
H
CH 3
C
H
C
CH 3
trans but-2-ene
7
[14]
Mill Hill High School
2
18.
(a)
(i)
ethyl ethanoate
H
H
O
C
C
O
H
(b)
H
H
C
C
H
H
H
(1)
2
(ii)
esterification / condensation / addition - elimination (1)
1
(i)
aqueous / dilute sulphuric / hydrochloric acid (allow HCl(aq); H2SO4(aq)
not water) (1)
temp. < 100° / warm / heat / reflux (this mark dependent on sensible reagent) (1)
2
(ii)
CH3COOC2H5 + H2O  CH3COOH + C2H5OH
(allow C4H8O2, C2H4O2 but must have C2H5OH) (1)
(c)
1
sodium hydroxide / sodium carbonate / sodium hydrogen carbonate
(allow formula) (1)
room temperature / aqueous (2nd mark dependent on correct reagent) (1)
(d)
2
ethanamide not ethylamide.
H
H
O
C
C
N
H
H
H
(1)
2
[10]
19.
(a)
(allow
O
CH 3 CH 2
C
COO
) (1)
1
(1)
OCH 2 CH 3
(b)
Name of mechanism: (nucleophilic) addition- elimination (1)
O
C
Mechanism: CH 3 CH 2
(1) :O
CH 3 CH 2
:O
(1)
Cl
H
CH 3 CH 2
C
Cl
O
H
CH 3 CH 2
structure
incl charges (1)
3 arrows (1)
5
[6]
Mill Hill High School
3
20.
(a)
2-chloropropanoic acid (1)
(b)
(1)
Cl
CH 3
CH
(1)
1
CH 3
COOH
CH COOH
+
N H ( :NH 3)
H
CH
COOH
NH 2
H (1)
(1)
:NH3
CH 3
(1)
Allow SN1
5
(c)
(i)
H
+
(Cl – ) H 3 N
(CH 2) 4
C
COOH
+NH 3
(ii)
(1)
–
(Cl )
H
H 2N
(CH 2) 4
C
COO – (Na + )
(1)
NH 2
(iii)
H
H 2N
(CONH)
O H H
C
C
N
or
C
COOH
(CH 2 )4
(CH 2 )4
NH 2
NH 2
H 2N
H
O
H
H
(CH 2 ) 4 C
C
N
(CH 2 ) 4 C
(1)
NH 2
COOH
NH 2
Or anhydride
3
[9]
21.
(a)
(b)
(c)
Lone pair on N (1)
accepts a proton (1)
2
(i)
Nucleophilic substitution or alkylation (1)
(ii)
Compound 1
(CH3CH2)2NH (1)
Compound 2
(CH3CH2)3N (1)
Compound 3
(CH3CH2)4N+Br–
Equation
CH3CN + 2H2  CH3CH2NH2 (1)
Reason
only one product formed (1)
4
2
[8]
(a)
electrophilic addition
H 2C
(1)
CH 2
Cl
Cl
Mill Hill High School
(1)
+
H 2C
(1)
(1)
–
Cl
CH 2
(1)
Cl
:
22.
5
4
(b)
CH 2
C 2 H 4 Cl 2
CH 2
H
H
or
C
Cl
C
H
+
HCl
(1)
1
(1)
1
(c)
Cl
ester or alkoxy alcohol
Cl
(d)
(i)
HO–CH2–CH2–OH
(1)
(ii)
high electron density of double bond
repels OH– or nucleophile
(1)
(1)
3
[10]
23.
(a)
ethanenitrile / ethanonitrile / methyl cyanide /
cyanomethane / acetonitrile
(1)
1
(b)
any hydrolysis
(1)
1
(c)
CH3COCl + CH3NH2 ® CH3CONHCH3 + HCl
for correct formula of methylamine / HCl product
(1)
overall correct
(1)
2
[4]
24.
(a)
(i)
2, 3 – dimethylbutan – 2 – ol (1)
(ii)
elimination (1)
Mechanism
(1)
H
+
(1)
OH2
(CH 3 ) 2 C
CH (CH3 ) 2
+
OH2
(CH 3 ) 2 C
CH (CH3 ) 2
(1) H
+
(CH 3 ) 2 C
C (CH 3 ) 2
(CH 3 ) 2 C
C (CH 3 ) 2
(1)
(iii)
Structure
CH (CH 3 ) 2
H2 C
(1)
C
CH 3
Name of isomer
Explanation
Mill Hill High School
2, 3 – dimethylbut – 1 – ene (1)
loss of H+ or H (1)
from end C also possible (1)
10
5
(b)
(i)
Equation
OH
(CH3 ) 2 C
OCOCH 3
CH (CH3 ) 2 + CH3 COCl
Name of mechanism
(CH3 ) 2 C
CH (CH3 ) 2 + HCl
(1)
addition – elimination (1)
Mechanism
Cl
(1)
R
R
O:
C
H
CH 3
+
O
(1) H
(ii)
(1)
O
R
Cl
(1)
+
O
C
O–
H
CH 3
allow loss
of H + here
O
C
CH 3
Type of reaction
Reagent(s)
Conditions
esterification (1)
CH3COOH or ethanoic acid (1)
strong acid catalyst (1)
or H2SO4 or HCL
9
[19]
25.
(a)
(b)
graphical structure for CH3CH2COOH (1)
allow CH3CH2– or C2H5–
(i)
1
ethanol / CH3CH2OH / C2H5OH not just alcohol (1)
(concentrated or dilute) sulphuric acid / HCl / strong acid / H+
not just acid solution
heat / reflux / warm / temperature < 100 °C (1)
allow second and third marks if alcohol given
third mark is dependent on first and second marks
second mark is independent on first mark
3
(ii)
ethyl propanoate (1)
1
(iii)
CH3CH2COOH + CH3CH2OH  CH3CH2COOCH2CH3 + H2O
C3H6O2 + C2H6O  C5H10O2 + H2O (minimum for mark) (1)
CH3CH2COOCH2CH3 or C2H5CO2C2H5 (1)
(c)
(i)
compounds with the same molecular formula /
same numbers of same atoms (1)
but different structural formulae / structures or (1)
atoms joined / bonded / linked in different orders / C skeletons
not atoms arranged differently
(ii)
2
2
sodium ethanoate / CH3COONa (1)
propan-1-ol / CH3CH2CH2OH / propanol / propan-2-ol (1)
2
[11]
Mill Hill High School
6
26.
(a)
Name
nucleophilic addition (1)
Mechanism
–
(1)
O
CH 3
C
–
NC:
(b)
CH 3
H+
O:
C
(1)
CH 3
CH 3
CN
(1)
(1)
5
Equation
CH3COCH3 + 2[H]  CH3CH(OH)CH3 (1)
Reducing agent
NaBH4 (1)
2
[7]
27.
(a)
Structure of P: CH 3
(1)
CH 2 CH 3
3
C
CH
CH 3
H
CH 2
CH 3
C
Structures of Q and R:
CH 3
and
C
CH 2 CH 3
H
H
C
C
CH(CH 3 )2
H
NOT C 3 H 7
(1)
(1)
Q and R in any order
(b)
(i)
Racemic mixture: equal mixture of optical isomers / enantiomers
OR in explanation
Explanation: planar ( >C=O) (1)
attack from either side is equally likely (1)
(ii)
Reagent S: HCN or (KCN / HCl or H2SO4) (1)
Compound T:
(1)
OH
CH 3 CH 2
C
CH 3
CN
Compound U: CH 3
CH 3 (1)
C
H
6
C
CN
[9]
28.
(a)
NaBH4
(1)
(b)
nucleophilic
addition
(1)
(1) H +
–
O:
(1)
O
CN
–
(1) :CN
(1)
Mill Hill High School
1
(1)
5
7
(c)
(i)
hexanedioic acid
(ii)
C6H10O
Mr = 98 (1)

2.40 g

(1)
C6H10O4
Mr = 146 (1)
2.40
× 146 = 3.58 g (1)
98
4
[10]
29.
(a)
(i)
nucleophilic addition
(ii)
2-hydroxybutanenitrile
H
(b)
(i)
H
H
H
C
C
C
H
H
H
C
(1)
condone missing hyphen
(c)
(1)
N
CH3CH2CH2Br + KCN  CH3CH2CH2CN + KBr
allow C3H7Br
(ii)
1
(1)
2
(1)
1
(1)
1
allow C4H7N
nucleophilic substitution / SN2
CN– or NC–
(1)
lone pair of electrons on C atom
(1)
2
[7]
30.
(a)
(b)
(c)
(d)
Lone pair on N or electron density on N
more available or electron density increased
electron donation or inductive effect
(1)
(1)
(1)
Reagent(s)
LiAlH4 or Na/EtOH or H2/Ni
(1)
Type of reaction
reduction or hydrogenation
(1)
Equation
CH3CN + 4[H] or 2H2  CH3CH2NH2
(1)
(C2H5)4N+Br–
(1)
quaternary ammonium salt
(1)
cationic surfactant
or fabric softener
(1)
Name of mechanism addition-elimination
(1)
3
3
3
Mechanism
C 2 H 5 NH 2
C
(1)
(1)
O
Cl
+
C 2 H 5 NH 2
CH 3
C
O
CH 3
+
C 2 H 5 NH
(1)
Mill Hill High School
:
Cl
:
(1)
H
O
C
CH 3
5
8
(e)
C2H5NH2 + (CH3CO)2O  C2H5NHCOCH3 + CH3COOH
or 2C2H5NH2 + (CH3CO)2O  C2H5NHCOCH3 + CH3COO–
(1)

H C H
N 3 2 5
1
[15]
31.
(a)
(i)
H+ or proton acceptor (1)
CH3NH2 + H2O ( ) CH3+NH3 (+) OH– (1)
(ii)
CH3NH3Cl or HCl (1)
Or any ammonium compound or strong acid
name or formula
(iii)
+
extra OH– reacts with CH 3 NH 3
or reaction / equilibrium moves to left
or ratio salt / base remains almost constant (1)
Any 2
5
(b)
(c)
lone pair (on N accepts H+) (1)
CH3 increases electron density (on N)
donates / pushes electrons
has positive inductive effect (1)
2
nucleophilic substitution (1)
C2 H 5
CH 3
+
N C2 H 5
(1)
2
C2 H 5
[9]
32.
(a)
(b)
2-amino(e) propanoic acid (1)
(i)
molecules with same structure / structural formula (1)
but with bonds (atoms or groups) arranged differently in space (3D) (1)
(ii)
(c)
Plane polarised light (1)
Rotated (equally) in opposite directions (1)
(1)
H
H2N
C
H
4
O
C
O–
allow H2NCH2COO–
Penalise NH2- and OH- once per paper
but CH3– is allowed
1
Mill Hill High School
9
(d)
CH 3
H2 N
C
H
H
(CONH)
O
C N C C
OH
O H H
H
H2 N
C
H
CH 3
C
N
O
C
H
O
C
(1)
(1)
OH
H
Not anhydrides; not repeating units
2
H
(e)
H2N
C
(1)
O
C
H
O
CH 3
or H2NCH2COOCH3
1
[9]
33.
(a)
elimination (1)
(b)
melting point increases (1)
boiling point increases(1)
or
they are liquids, the higher members are solids(1)
density increases(1)
viscosity increases(1)
(c)
(d)
max 2
addition (1)
polymerisation (1)
2
(i)
C2H4 + H2O C2H5OH - must show the functional group (1)
1
(ii)
vapour phase / high temperature (300 ± 50°C) (1)
high pressure 70cl ± 20 (1)
if high T and high p, then only 1 mark, value for either gives 2nd mark
strong acidic catalyst /H3PO4 (1)
(iii)
3
electrophilic (1)
addition (1)
2
[11]
Mill Hill High School
10
34.
(a)
(i)
(ii)
the joining together of monomers / small molecules
(1)
to form long chains / large molecules
(1)
nCH2 = CH2
 (-CH2–CH2-)n
(1)
allow n CH2 CH2 not n C2H4
1
(b)
1,2-dibromoethane
(1)
(c)
electrophilic addition
(1)
H
H
C
C
H
Br
Br
(d)
+
H
H
H
H
C
C
Br
:Br –
H
H
H
H
C
C
Br
Br
–
(1)
correct carbocation intermediate (allow triangular representation)
(1)
attack by Br– (onto +ve carbon) leading to correct product
(1)
(i)
(1)
(iii)
1
H
words or diagrams to show attack by p electrons on Br atom
and either +/– on Br2 or e– shift on Br–Br
(ii)
2
C 38.71/12 = 3.23 ;
H 9.68/1 = 9.68 ;
O 51.61/16 = 3.23
ratio C:H:O = 1:3:1 /empirical formula = CH3O
(1)
empirical mass = 31 so molecular formula = 2 × CH3O = C2H6O2
(1)
reagent = NaOH / KOH
(1)
conditions = aqueous solution (dependent on first mark)
(1)
CH2BrCH2Br + 2NaOH 
4
3
2
CH2(OH)CH2OH + 2NaBr
product = CH2(OH)CH2OH (condone missing brackets)
(1)
correctly balanced
(1)
2
if C2H6O2 given, allow second mark only
for CH2 Br CH2 Br + 2H2O  CH2(OH)CH2(OH) + 2HBr
allow 2 marks if reagent in (ii) is H2O or aqueous solution
[15]
35.
(a)
(i)
O
O
C
1
C
HO
OH
(ii)
H
Mill Hill High School
(1)
O
H
H
C
C
H
H
allow HOCH2CH2OH (1)
O
1
H
11
O
O
C
(iii)
C
O
O
H
H
C
C
H
H
n
ester linkage correct ie –COO–CH2– shown as fully graphical structure (1)
rest of molecule correct including
n
(1)
repeat unit may start and finish in different place
allow e.c.f. from (a)(ii)
2
(b)
polyesters (1)
(c)
addition: joining together (of monomers with double bond) 
one product only (1)
(d)
1
condensation: also involves the elimination of a small molecule (1)
allow specific example e.g. H2O, HCl, CH3OH
2
poly(ethene) / poly(propene)
condone missing brackets (1)
1
[8]
(a) add Fehling’s, warm, should see orange precipitate
or add Tollen’s, heat, should see silver mirror (3)
propenoic acid (1)
(b)
36.
H
H
C
H
C
H
H
CHO
H
+
Br
Br
C
C
H
H
H
C
C
+
H
CHO
Br
Br :
CHO
Br
(4)
electrophilic addition (1)
[9]
SECTION C – LONG ANSWERS
37.
(a)
3 Ketones:
CH 3
CH 3 CH 2 CH 2 C CH 3 (1)
O
CH 3
CH
C
O
CH 3 (1)
CH 3 CH 2 C CH 2 CH 3 (1)
O
3
(b)
4 aldehydes:
Mill Hill High School
12
CH 3
H
CH 3 CH 2 CH 2 CH 2
(1)
C
CH 3
O
H
CH
CH 2
(1)
C
O
CH 3
H
CH
CH 3 CH 2
H
(1)
C
CH 3
O
CH 3
Y (1)
(c)
O
CH 3
Z (1)
nucleophilic
(1)
C
C
X (1)
5
addition (1)
equal (1) mixture of optical isomers (1)
CH 3 CH 2
e.g
4
(1)
C
CH 3 CH 2
(d)
OH
CN
Reagents are oxidizing agents (1)
Aldehydes can be (easily) oxidized (1)
Ketones are not (easily) oxidized (1)
3
[15]
38.
nucleophile = electron pair donor or
electron rich species which seeks electron deficient site (1)
1
With C2H5Br :
reagent : KCN (1)
product : propanenitrile (1)
mechanism : nucleophilic substitution (1)
(1)
CH 3
(1)
CH 2
–
CH 3 CH 2 CN + :Br
Br
(1)
–
:CN
6
With CH3CH2CHO
reagent : HCN (1) (or KCN/H+)
product : 2–hydroxybutanenitrile (1)
mechanism : nucleophilic addition (1)
H
CH 3 CH 2
(1)
(1)
C
–
:CN
H
CH 3 CH 2
O
(1)
C
CN
–
O:
H+
(1)
O
CH 3
C
(1)
O
CH 2 CH 2 CH 3
8
[15]
39.
3-bromo, 3-methylbut-1-ene (1)
the mechanism proceeds via a tertiary carbocation (1)
Mill Hill High School
13
other products are formed via primary or secondary carbocations (1)
which are less stable so less abundant (1)
4
[4]
40.
(a)
fractional or primary distillation not just distillation (1)
crude oil is useless (1)
or products are more useful / valuable than crude oil
(b)
2
heat / high temperature (400 °C – 600 °C) (1)
catalyst / steam / high pressure /
named catalyst known to work eg Al2O3 (1)
C4H10  C2H4 + C2H6 or C4H10  2C2H4 + H2 (1)
(c)
3
2C2H4 + O2  2CH3CHO (1)
2CH3CHO + O2  2CH3COOH (1)
not [O]; not molecular formulae
(d)
CH 3
C
O
(e)
CH 3 (1)
C
O
2
1
O
ethene < ethanal < ethanol < ethanoic acid (2)
give 1 mark for ethene < ethanal < ethanol
give 1 mark for ethanol < ethanoic acid
ethene has van der Waals’ forces / weak intermolecular forces (1)
ethanal has (permanent) dipole-dipole attractions not just ‘ethanal is polar’ (1)
ethanol has hydrogen bonding (1)
ethanoic acid has more or stronger hydrogen bonding / forms dimers (1)
mark reasons independently of order
6
[14]
41.
(a)
A
H
H
H
H
C
C
C
H
H
H
H
C H
H
B
C
O
H
H
C
C
C
C
H
O
H
H
H
(1)
H
CH 3
C
C
H
H
H
D
H
(1)
H
C
C
H
O
O
H
C
O
(1)
H
H
C
C
H
H (1)
H
A = butanal
B = methylpropanal
Mill Hill High School
14
C = butanone
D = ethyl ethanoate (1)
Ignore numbers in names unless they make them incorrect
spellings must be correct
accept alternative trivial names correctly spelled
(b)
8
ethanol / correct formula (1)
ethanoic acid / ethanoyl chloride / ethanoic anhydride / correct formula (1)
temperature less than 100 °C / reflux heat / concentrated sulphuric acid (1)
dilute sulphuric acid / acid conditions / H+
(this mark dependent on sensible answers for first two marks)
for ethanoyl chloride, room temperature / dry / anhydrous
for ethanoic anhydride, heat / up to 100 °C
H
H
H
O
(c)
H
C
C
C
H
H
H
3
or
C
O
H
H
H
CH 3
C
C
H
H
O
C
O
H (1)
(1)
butanoic acid
(d)
methylpropanoic acid (1)
2
heat with Fehling’s solution / ammoniacal silver nitrate / Tollen’s reagent /
other suitable oxidising system eg acidified dichromate / Schiff’s reagent
B gives red, green or brown (precipitate) / silver (mirror) or black/grey (1)
precipitate / other, dependent on reagent
C shows no change (1)
B and C can be referred to as ‘aldehyde’ and ‘ketone’ only if names correct
in (a) or if there is some other valid identification
(e)
3
nucleophilic addition (1)
–
CH 3
CH 3
C
O
C
–
CH 3 CH 2
(1)
O
CN
CH 3 CH 2
H
CN
(1) for intermediate
allow –ve charge on N
but curly arrow must come from C
CH 3
+
OH
C
CH 3 CH 2
CN
(1) for product
allow H from HCN or H2O
5
[21]
42.
(a)
1, 4-diaminobutane or butane -1, 4-diamine (1)
A: BrCH2CH2Br or ClCH2CH2Cl (1)
B: NC CH2CH2CN
Step 1: Br2 or Cl2 (1) (ignore aq)
Step 2: KCN (1) (NOT HCN)
Step 3: H2 / Ni or LiAlH4 or Na / C2H5OH (1) (NOT NaBH4)
Hydrogenation only for H2 / Ni, or nucleophilic addition only for LiAlH4(1)
OR reduction or addition
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15
7
(1)
(b)
N
(CH 2 ) 4 N
C
(CH 2 )4 C
H
H
O
O
(1)
QL hydrogen bonding (1)
Polarity of H-bonding shown or discussed (1)
(c)
4
Polyamides / peptide link can be hydrolysed (1)
OR polyalkenes cannot be hydrolysed
QL OH– attacks peptide link or C+ (1)
poly(ethene) non-polar (1)
3
[14]
43.
COOH
COOH
C
C
H2N
CH3
NH2
CH3
H
H
(2)
asymmetric/ chiral carbon atom (1)
3
[3]
44.
(a)
combination of several unsaturated molecules (1)
to form a single saturated molecule (1)
(b)
(i)
2
G: hexan-1,6-diol (or structure) (1)
H: 1,6-dichlorohexane (or structure) (1)
J: hexan-1,6-dioyl dichloride (or structure) (1)
K: hexan-1,6-diamine (or structure) (1)
Reaction 3: nucleophilic substitution (1)
Reaction 5: nucleophilic addition-elimination (1)
6
(ii)
O
O
C
(CH2)4
C
N
H
(CH2)6
N
H
n
2
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(iii)
O
+
R
C
Cl
H
N
R
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H
-
OO
R
C
Cl
R
R
O
R
C
+
N
+
N
H
Cl
+ HCl
C
N
H
H
R
H
H
R
5
[15]
17