1

IR WS 1
1 B
2 C
3 C
4 B
5 C
6 C
7 C
8 B
9 C
10 D
11 A
12 C
13 A
14 C
15 C
16 C
17 B
18 A
19 D
20 D
21 B
22 B

Bilal Hameed IR 1
 2

Page 8
IR WS 2
Mark Scheme Syllabus Paper
Cambridge International AS/A Level – March 2016 9701 22

1 2016 MAR P22 Q05

Question Answer Mark Total

(b) This question was discounted.

[1]
M1 = decolourises bromine / 1500–1600 cm–1 = alkene [1]
M2 = absorption at 1700!cm–1 is C=O
AND
(very) broad absorption at 2500–3000!cm–1 is O—H = carboxylic acid [1]
M3 = no cis-trans so terminal alkene [4]
OR
chiral so contains a carbon atom with 4 different groups attached [1]
M4 = U is

[10]

© Cambridge International Examinations 2016

IR 2 Bilal Hameed
 Page 6 Mark Scheme Syllabus Paper
Page 6 Mark AS/A
Cambridge International Scheme
Level – May/June 2016 Syllabus
9701 Paper
21
Cambridge International AS/A Level – May/June 2016 9701 21
Question Mark Scheme Mark Total
Question Mark Scheme Mark Total
(d)
(d)
B is CH2=CHCH2CH3 OR CH3CH=CHCH3 OR (CH3)2C=CH
B is CH2=CHCH2CH3 OR CH3CH=CHCH3 OR (CH3)2C=CH2
3 2 [1]
[1]
distinguished by addition of bromine [1] [3]
distinguished by addition of bromine [1] [3]
brown/red/orange/yellow to colourless/decolourises with B (but not A) [1]

2 2016 JUN P21 Q05

brown/red/orange/yellow to colourless/decolourises with B (but not A) [1]
[7]
[7]
5 (a)
5 (a)

[2]
[2]

M1 = lone pair on C of CN− AND curly arrow from lone pair to C of C—Br [1]
M1 = lone pair on C of CN− AND curly arrow from lone pair to C of C—Br [1]
M2 = correct dipole on C—Br, curly arrow from C—Br bond to Br AND Br− [1]
M2 = correct dipole on C—Br, curly arrow from C—Br bond to Br AND Br− [1]
(b) (i) reduction [1] [1]
(b) (i) reduction [1] [1]
(ii) disappearance of peak / dip / trough / absorption at 1680–1730 [1]
(ii) disappearance of peak / dip / trough / absorption at 1680–1730 [1]
due to (loss of) C=O [1]
due to (loss of) C=O [1]
OR [2]
OR [2]
peak at 3200–3650 [1]
peak at 3200–3650 [1]
due to (alcohol) O—H (formation) [1]
due to (alcohol) O—H (formation) [1]
Page 7 Mark Scheme Syllabus Paper
(c) (i) sodium/potassium hydroxide [1]
(c) (i) Cambridge International AS/A Level – May/June 2016
sodium/potassium hydroxide 9701 21 [1] [2]
aqueous [2]
aqueous [1]
Question Mark Scheme
© Cambridge International Examinations 2016 Mark Total
© Cambridge International Examinations 2016
(ii) ethanol [1] [1]

(d) (i) (conc) H+ / (conc) acid / (conc)H2SO4 / (conc)H3PO4 [1] [1]

(ii)

[1] [1]

(iii) ethyl propanoate [1] [1]

(e) (i) V = CH3CH2CHCHCH2CH3 / CH3CH2CH=CHCH2CH3 [1]

[2]
T = CH3CH2CH(OH)CH(OH)CH2CH3 [1]

(ii) V = geometric(al) / cis-trans / E–Z [1]

[2]
T = optical [1]

[15]

© Cambridge International Examinations 2016

Bilal Hameed IR 2
 4
Page 5 Mark Scheme Syllabus Paper
Cambridge International AS/A Level – May/June 2016 9701 22

3 2016 JUN P22 Q04

Question Answer Mark Total

4 (a) CH3CH2CH2COOH [1]

(CH3)2CHCOOH / CH3CH(CH3)COOH [1] [2]

(b) (i) Two from

1. CH3CH2COOCH3 2. CH3COOCH2CH3 3.HCOOCH2CH2CH3 [1]
[1] [2]

(ii) correct acid + alcohol for either ester [1]

1. methanol + propanoic acid
2. ethanol + ethanoic acid
3. propan-1-ol + methanoic acid

(conc)H2SO4 / (conc)H3PO4 AND heat / warm / reflux [1] [2]

(c) Peak at 1710–1750 (for ester) due to C(=)O [1]

Peak at 1500–1680 (for X) due to C(=)C / alkene [1]
Peak at 3200–3650 (for X) due to (alcohol) O(–)H [1] [3]

[Total 9]

5 (a) (i) acidified / H+

AND

potassium / sodium dichromate [1] [1]

(ii) distillation (rather than reflux) [1]

(ensures aldehyde escapes) to avoid further oxidation / to avoid forming acid / as reflux causes further oxidation [1] [2]

© Cambridge International Examinations 2016

IR 2 Bilal Hameed
 1 [1] [3]
(iii) NO + 2
O2 → NO2
[1]
NO2 + SO2 → SO3 + NO
[1]
SO3 + H2O → H2SO4 / 2H+ + SO42– / H+ + HSO4–

(iv) lowers pH of rivers / lakes / kills fish

leaches (toxic) aluminium from soil (into rivers / lakes)
5 [1]
[1]
[max 2]

leaches away soil nutrients [1]

damage to buildings / statues / trees / plants / crops [1]
ocean acidification / damage to coral [1]

4 2016 JUN P23 Q04 [17]

4 (a) 3-hydroxybutan(-2-)one [1] [1]

(b) H2 / Cr2O72– or names [1] [2]

heat / reflux / warm [1]

Page 5 Mark Scheme Syllabus Paper
(c) (i) absorption at 1670–1740 C (=) O
Cambridge International AS/A Level – May/June 2016 9701 23 [1] [3]
absorption at 2850–3000 C (-) H [1]
absorption at 3200–3650 O (-) H [1]
Question Mark Scheme Mark Total

(ii) no absorption at 3200–3650 [1] [2]

O-H disappears / no O-H bond in diacetyl [1]
© Cambridge International Examinations 2016
(d) (i) CH3COCH(=)CH2 [1] [1]

(ii) one of the double-bonded C atoms / first C has 2H atoms attached ora [1] [2]
so no cis-trans / E-Z / geometric(al) isomerism possible
OR
no chiral C [1]
so mirror images superimposable / molecule not asymmetric

(iii) asymmetric / chiral C atom / carbon with four different groups / atoms attached [1] [1]

(iv) C O CH3 H3C OC [1+1] [2]

C C
H H
Br CH3 H3C Br

[14]

© Cambridge International Examinations 2016

Bilal Hameed IR 2
 1
T=

1
6
U=

5 2017 MAR P22

3(c)(v) Q03 2CH3
CH3CHOHCH + [O] → CH3COCH2CH3 + H2O 1

3(d)(i) methyl pentanoate 1

3(d)(ii) (compound V is) spectrum X 1

spectra X and Z show a C=O (stretch) at 1730 (cm–1) 1

spectra Y and Z show O–H (stretches) above 2500 (cm–1) 1

V has a C=O (bond) and no O–H (bond) 1

© UCLES 2017 Page 5 of 5

IR 2 Bilal Hameed
 4(b)(ii) 2C4H8O2 + Na2CO3 2C4H7O2Na + H2O + CO2 1

4(c)(i) triiodomethane 1

4(c)(ii) F = CH3CH2CH2COCH3 7 1

G = C2H5CH(CH3)CHO 1

4(c)(iii) a (tetrahedral) atom with four different groups / atoms / substituents attached 1
OR
6 2017 JUN P22
a carbon Q04
(atom) with four different groups / atoms / substituents attached

4(d)(i)
9701/22 H C=O (group / bond) AND O–H (group / bond) International AS/A Level – Mark Scheme
Cambridge May/June 20171
PUBLISHED
I C=O (group / bond) AND C–H (group / bond) 1
Question Answer Marks

4(d)(ii) H = ethanoic acid 1

I = methyl methanoate 1

Total: 23

© UCLES 2017 Page 8 of 9

© UCLES 2017 Page 9 of 9

Bilal Hameed IR 2
 Question Answer Marks

4(a)(i) ultraviolet / UV light 1

4(a)(ii) initiation 4
HCl
propagation 8

7 2018
4(b) MAR P22 Q04
elimination 1

4(c)(i) acidified AND KMnO4 2

hot AND c(oncentrated)

4(c)(ii) cyclohexene would have absorption at 1500–1680 (cm–1) because of C=C (and adipic acid would not) max 3

cyclohexene would have absorption at 3000–3100 (cm–1) because of =C—H/C—H in alkene (and adipic acid would not)

adipic acid would have absorption at 2500–3000 (cm–1) because of O—H/CO2—H (and cyclohexene would not)

adipic acid would have absorption at 1040–1300 (cm–1) because of C—O (and cyclohexene would not)

adipic acid would have absorption at 1640–1750 (cm–1) because of C=O (and cyclohexene would not)

© UCLES 2018 Page 7 of 7

IR 2 Bilal Hameed
 9

9701/21 Cambridge International AS/A Level – Mark Scheme October/November 2018

PUBLISHED
8 2018
QuestionNOV P21 Q04 Answer Marks

4(d)(i) EITHER 2
Glycolic acid would have:
M1 2500–3000 due to RCO2 H
M2 range within 3200–3650 due to RO–H

OR

Spectrum Y would NOT have:

M1 2500–3000 due to RCO2 H
M2 range within 3200–3650 due to RO–H

4(d)(ii) O 2
O O
O

M1 ANY ester group AND valid C4H4O4 molecule

M2 correct cyclic structure

© UCLES 2018 Page 9 of 9

Bilal Hameed IR 2
 M3 –82.4 [1]

3(b)(i) 1 mark for each bullet, max 3 3

• particles / molecules have (mass but) negligible size / volume (compared to total volume of gas / container)
• no / negligible forces / interactions between particles / molecules
• collision between particles / molecules are elastic 10
• gas obeys (all) basic gas laws

3(b)(ii) M1 particles / molecules are (so) close [1] 2

M2 particle / molecule size becomes significant [1]
OR
9 2018 NOV P22 Q03 repulsive forces between particle / molecules become significant

3(c)(i) CHCl3 + ½O2 COCl2 + HCl 1

–1
3(c)(ii) M1 X marked on peak at 1670–1740 cm [1] 2
M2 CHCl3 has no C=O [1]

3(c)(iii) (It / CHCl3 has a) peak at 2850–2950 (cm–1) 1

OR
carbonyl dichloride spectrum has no peak 2850–2950 (cm–1)

© UCLES 2018 Page 7 of 10

IR 2 Bilal Hameed
 11

9701/22 Cambridge International AS/A Level – Mark Scheme March 2019

PUBLISHED
10 2019 MAR P22 Q03
Question Answer Marks

3(e) 3
P Q R

Na(s) effervescence no reaction no reaction

2,4-DNPH no reaction orange ppt orange ppt

acidified
no reaction no reaction (turns) green
K2Cr2O7(aq)

3(b) C5H10O + 2[H] C5H12O 1

3(c) M1 geometric(al) 2

M2

3(d) M1 compound P 3

M2 (absorption at) 2250 cm–1 AND C N (stretch)

M3 (absorption at) 3100–3700 cm–1 AND O—H (stretch)

Question Answer Marks

4(a) 3-chloroprop-1-ene 1

4(b)(i) ultra-violet (light) / sun(light) 1

4(b)(ii) CH2=CHCH3 + Cl CH2=CHCH2 + HCl 1

OR C3H6 + Cl C3H5 + HCl

© UCLES 2019 Page 8 of 9

Bilal Hameed IR 2
 9701/21 Cambridge International AS/A Level – Mark Scheme October/November 2019
PUBLISHED
Question Answer Marks
12
4(b)(iv) 2

M1: / CH3CH(OH)CH3

11 2019 NOV P21

M2: H SO / Q04
sulfuric acid
2 4

4(c)(i) • orange / red / yellow precipitate 1

• orange / red / yellow precipitate

4(c)(ii) Aldehyde 1

4(c)(iii) has a carbon / atom attached / bonded to four different atoms / groups / groups of atoms / chains 1

4(c)(iv) 2

M1: Correct 3D representation

M2: Correct 3D representation of drawn enantiomer

4(c)(v) 1
principal absorptions in bond responsible
the infra-red spectrum

3200–3600 cm–1 RO-H / O-H

1630 cm–1 C=C

9701/21 Cambridge International AS/A Level – Mark Scheme October/November 2019
1050 cm–1 C—O PUBLISHED
Question Answer Marks

4(c)(vi) 3
© UCLES 2019 Page 8 of 9

OR
M1: skeletal alkene group AND C5 structure

M2: one alcohol group

M3: branched chain AND capable of geometrical isomerism

4(c)(vii) M1: Correct structure of X and correct dipole on C=O 3

M2: curly arrow from C=O bond to O AND intermediate with CN attached and –ve charge on the O

M3: curly arrow from lone pair on CN– to C(=O) in X

AND
curly arrow from lone pair in the intermediate to H+

4(c)(viii) catalyst 1

© UCLES 2019 Page 9 of 9

IR 2 Bilal Hameed
 Question Answer Marks

4(d)(iii) M1: skeletal formula of Q 2

13
ONLY

M2: one commercial use of Q (ethyl isovalerate / ethyl 3methylbutyrate)

12 2019 NOV P22

solvents Q04/ flavourings
/ perfumes

4(e)(i) 1500–1680 (cm–1) AND C=C 1

4(e)(ii) potassium cyanide / KCN / sodium cyanide / NaCN 1

4(e)(iii) (acidic) hydrolysis 1

4(e)(iv) M1: recognise this reaction involves less stable intermediate 2

1° (carbo)cation (intermediate) is less stable (than 3°)

M2: explain difference in reactivity in terms of positive inductive effect – comparative answer
lower (positive) inductive effect / lower (+)I
OR
inductive effect of less alkyl groups

© UCLES 2019 Page 10 of 10

Bilal Hameed IR 2
 14

9701/22 Cambridge International AS & A Level – Mark Scheme March 2020

PUBLISHED
13 2020
QuestionMAR P22 Q03 Answer Marks

3(d)(i) M1 3

M2 (two) different groups on each C atom in the C=C / end of the C=C double bond

M3 no / restricted rotation about C=C

3(d)(ii) H2 / hydrogen 1

3(d)(iii) M1 / M2 absorptions seen in both spectra (any two): 3

(same) both show an absorption at 1680–1730 (cm–1) because of C=O
(same) both show an absorption at 1040–1300 (cm–1) because of C–O
(same) both show an absorption at 2500–3000 (cm–1) because of RCO2–H / O–H in RCO2H / carboxyl(ic acid)

M3 absorption only seen in spectrum of T:

(different) T shows an absorption at 1500–1680 (cm–1) because of C=C
(different) T shows an absorption at 3000–3100 (cm–1) because of (C=)C–H

© UCLES 2020 Page 10 of 10

IR 2 Bilal Hameed
 5(d)(i) Two structures representing the intermediate 2
M1 C2H5C+HCH3
M2 CH3CH2CH2C+H2

5(d)(ii) Identify the most stable intermediate 2

M1 C2H5C+HCH3
15
explanation
M2 (more / 2 alkyl groups attached so) it has the greater inductive / electron donating effect

14 2020
QuestionJUN P21 Q06 Answer Marks

6(a) 1

6(b)(i)
9701/21 hot AND concentrated Cambridge International AS & A Level – Mark Scheme 1
May/June 2020
PUBLISHED
6(b)(ii) oxidation 1
Question Answer Marks

6(c) Structural formula of X: 1

© UCLES 2020 HCO2H OR HCOOH Page 9 of 10

6(d) M1 reagent (2,4–) DNPH / (2,4)-dinitrophenylhydrazine 2

M2 observation yellow / orange / red precipitate

6(e) Predict two differences, with reasons, between spectra of Y, CH3CH2COCH3 and 2-methylbut-1-ene (shown) 2
first difference
M1 absence of peak/ absorption at 3100 (cm–1) as no longer any =C–H present (in Y)

second difference
M2 peak at 1650 (cm-1) moves to the left to any value / range of values between 1670 and 1740) due to disappearance of
C=C (in Y) and appearance of C=O (in Y)
OR
absence of peak at 1650 (cm-1) as no longer any C=C present (in Y)
AND
appearance of peak (in Y) at (any value / range of values) between 1670-1740(cm-1) due to C=O

6(f)(i) CH3CH2CO2H + 4[H] → CH3CH2CH2OH + H2O 1

6(f)(ii) propan-1-ol 1
ALLOW propan-2-ol as error carried forward from 6f(i)

6(g)(i) Molecular formula of W 1

C3H6O2

6(g)(ii) Possible structure of W 1

CH3COOCH3 OR HCOOCH2CH3

© UCLES 2020 Page 10 of 10

Bilal Hameed IR 2
 M2: TWO correct co-ordinate bonds identified

3(a)(ii) 120 16 1

3(a)(iii) Li+ is 1s2 H– is 1s2 1

3(a)(iv) (Lattice of) cations / positive ions surrounded by delocalised electrons’ 1

15 2020
3(b) NOV P21
Al(OH) Q03hydroxide
/ aluminium 3 1

3(c)(i) M1: potassium dichromate[(VI)] 2

M2: acid(ified) AND (heat under) reflux

3(c)(ii) (M1: correct identity of R and statement re: reaction 3 ONLY ketone reduced) 2

R (is 2-hydroxybutanoic acid) AND as (only) C=O / ketone reduced

(M2: correct explanation re: strength of reducing agents)

NaBH4 cannot reduce the COOH / carboxylic acid
9701/21 Cambridge International AS & A Level – Mark Scheme October/November 2020
OR
PUBLISHED
LiAlH4 can reduce the COOH / carboxylic acid
Question Answer Marks

3(c)(iii) 4

© UCLES 2020 Page 8 of 11

M1: Presence of :CN (if bonding shown, must be unambiguous triple bond)
M2: curly arrow from :CN lone pair to carbonyl carbon
M3: correct dipole AND curly arrow from double bond to oxygen
M4: correct intermediate drawn

3(c)(iv) C2H5CH(OH)CN + HCl + 2H2O C2H5CH(OH)COOH + NH4Cl 1

3(c)(v) Any two of three absorption references: 2

• absorption 2200–2250 (cm–1) shows presence of C N
• lack of absorption at 1680–1730 (cm–1) shows lack of C=O
• lack of absorption at 2500–3000 (cm–1) shows lack of RCO2–H / O–H in RCO2H

© UCLES 2020 Page 9 of 11

IR 2 Bilal Hameed
 4(c) 3
reagent result with P result with Q

Br2(aq) no change / no change /

stays orange stays orange
17
2,4-DNPH no change orange ppt

Na2CO3 effervescence no change

16 2020 NOV
Award P22 Q04
one mark for every two correct observations.

4(d)(i) X is C=O AND Z is C—O 1

4(d)(ii) hexanoic acid 1

4(d)(iii) C12H20O2 1

© UCLES 2020 Page 11 of 11

Bilal Hameed IR 2
 18

9701/22 Cambridge International AS & A Level – Mark Scheme May/June 2021

PUBLISHED
17 2021 JUN P22 Q05
Question Answer Mark

5(a) displayed formula of butan-2-ol structure with O—H shown 1

5(b)(i) 2-bromobutane 1

5(b)(ii) substitution 1

5(b)(iii) reagent 1
M1 NaCN or KCN

conditions 1
M2 ethanolic AND heat (under reflux)

5(b)(iv) (1)C4H9CN + (1)H+ + 2H2O (1)C4H9CO2H + (1)NH4+ 1

correct organic product showing carboxylic acid functional group
M1 C4H9CO2H / C4H9COOH

M2 balanced equation with a C5H10O2 or equivalent structure as product 1

5(b)(v) 2200–2250 (cm–1 due to) C N / triple bond between C and N. 1

© UCLES 2021 Page 12 of 12

IR 2 Bilal Hameed
 PUBLISHED
Question Answer Marks

3(c)(iii) 2
G = C2H5CH2OH H = C2H5CH=CHC2H5
19
3(d) 2
CH3CH2CO2H CH3COCH3

18 2021 NOV P21 Q04

Question Answer Marks

4(a)(i) potassium/sodium dichromate [(VI)] / K2Cr2O7 / Na2Cr2O7 2

acidified AND (heat) under reflux

4(a)(ii) C2H5OH + 2[O] CH3CO2H + H2O 1

4(a)(iii) substitution 1

4(a)(iv) in the same phase / in same state 1

4(b) M1 ester 3

M2 1100 cm–1 linked to C—O AND 1720 cm–1 linked to C=O

M3 No COOH / carboxylic acid and No OH / alcohol in D (but present in C)

OR

COOH / carboxylic acid and OH / alcohol reacted /lost (in C to form D)

4(c)(i) 1

OR Na+

4(c)(ii) Not a strong (enough) reducing agent 1

© UCLES 2021 Page 9 of 10

Bilal Hameed IR 2
 OR

OR OR

3(c)(i) 1
20

19 2021
3(c)(ii) NOV
sp P22 Q03
2 1

3(d)(i) cold dilute acidified potassium manganate(VII) 1

3(d)(ii) M1 (2,4-DNPH will produce a) red / orange / yellow precipitate 2

M2 V has a carbonyl group

3(d)(iii) M1 C—O in range 1040–1300 (cm–1) 2

M2 C=O in range 1670–1740 (cm–1)

3(e)(i) yellow precipitate 1

3(e)(ii) Iodine / I2 1

3(e)(iii) C6H12O + 2[H] C6H14O 1

© UCLES 2021 Page 10 of 11

IR 2 Bilal Hameed