Organic Chem Ans

1. C[1]

2. B[1]

3. C[1]

4. B[1]

5. (a) boiling points increase (from the first member to the fifth member);

increasing size of molecule/area of contact/number of electrons (from

the first to the fifth member);

strength of intermolecular/van der Waals’/London/dispersion forces

increase / more energy required to break the intermolecular bonds

(from first member to fifth member); 3

(b) same general formula;

successive members differ by CH2;

same functional group / similar/same chemical properties;

gradual change in physical properties; 2 max

Accept specific physical property such as melting point, boiling

point only once.[5]

IB Questionbank Chemistry 1

6. A:

B:

C:

1,2-dichloroethane;

D:

Accept condensed formulas. 5

Penalize missing hydrogens only once.[5]

7. add bromine water/bromine;

pentane no change/stays brown and pent-1-ene decolourizes bromine

water/bromine;

OR

add acidified KMnO4;

pentane no change/stays purple and pent-1-ene decolourizes acidified KMnO4; 2 max

Accept any correct colour change.

Do not accept “clear” instead of “colourless”.[2]


8. E: primary and F: secondary;

G: primary;

G / E: only one alkyl group/2 H atoms attached to the carbon atom

attached to the Cl / only one carbon atom attached to the carbon atom

attached to the Cl;

F: two alkyl groups/1 H atom attached to the carbon atom attached to

the Cl / two carbon atoms attached to the carbon atom attached to the Cl; 4[4]

9. Initiation:

Cl2 2Cl•; →heathvhf //UV/

Reference to UV/hf/hν/heat must be included.

Propagation:

Cl• + CH4 → CH3• + HCl;

CH3• + Cl2 → CH3Cl + Cl•;

Termination:

Cl• + Cl• → Cl2 / CH3• + Cl• → CH3Cl / CH3• + CH3• → C2H6; 4

Allow representation of radical without • (e.g. Cl, CH3) if consistent

throughout mechanism.

If representation of radical (i.e. •) is inconsistent, penalize once only.[4]

10. (a) but-1-ene;

Allow 1-butene.

CH3–CH2–CH=CH2; 2

(b) C2H5–CH(OH)–CH3 → C2H5–CH=CH2 + H2O;

heat and (concentrated) phosphoric acid/H3PO4/sulfuric acid/H2SO4; 2


(c)

curly arrow going from C=C to Br of Br2 and curly arrow showing Br

atom leaving Br2 molecule;

representation of carbocation;

curly arrow going from lone pair/negative charge on Br– to C+; 3

(d) butan-1-ol gives higher yield / butan-2-ol gives lower yield;

butan-2-ol will give but-2-ene as well as but-1-ene / butan-1-ol

will only give but-1-ene; 2[9]

11. chlorobutane more rapid;

steric hindrance/repulsion by electron cloud from benzene ring in chlorobenzene;

C–Cl bond less polar/charge on C–Cl carbon smaller (owing to polarization of

delocalized electrons);

C–Cl bond stronger (owing to partial π-bonding by lone pair); 3 max

Any 2 of the above for second and third marks.

Accept opposite statements for chlorobutane.

No ECF for second and third marks.[3]

12. (CH3)2CH–Mg–Cl;

anhydrous / absence of water / ether solvent; 2[2]

13. (i) propanone/CH3–CO–CH3 and hydrogen cyanide/HCN/cyanide ion/CN–; 1


(ii)

1[2]

14. (a) amine salt;

[(CH3)2NH2]+ + OH– → (CH3)2NH + H2O /

[(CH3)2NH2]Br + OH– → (CH3)2NH + Br– + H2O /

[(CH3)2NH2]+ + NaOH → (CH3)2NH + Na+ + H2O /

[(CH3)2NH2]Br + NaOH → (CH3)2NH + NaBr + H2O; 2

(b) greater / more alkaline;

the inductive/e– donating effect of the methyl groups reduces

the charge on the nitrogen atom of the cation / stabilizes the

cation / OWTTE;

OR

the inductive/e– donating effect of the methyl groups increases

the negative charge on the nitrogen of the amine so that it attracts

H+ ions more strongly / OWTTE; 2[4]

15. D[1]

16. B[1]

17. A[1]

18. A[1]


19.

Accept condensed formulas. 5

Award [1 max] if A and D are other way round (and nothing else correct).

Award [2 max] if A and D are other way round but one substitution product

B or E is correct based on initial choice of A and D.

Award [3 max] if A and D are other way round but both substitution

products B and E are correct based on initial choice of A and D.

M2 (for B) and M5 (for E) may also be scored for substitution product

if primary chloroalkane used.

Penalize missing hydrogens once only.[5]


20. CH3CH2COOH + CH3OH CH3CH2COOCH3 + H2O

[1] for reactants and [1] for products.

(concentrated) sulfuric acid/H2SO4;

Do not accept just H+ or acid.

methyl propanoate; 4[4]

21. (i)

curly arrow going from lone pair/negative charge on O in HO– to C;

Do not allow curly arrow originating on H in HO–.

curly arrow showing Cl leaving;

Accept curly arrow either going from bond between C and Cl to Cl in

2-chloro-3-methylbutane or in the transition state.

representation of transition state showing negative charge, square

brackets and partial bonds;

Do not penalize if HO and Cl are not at 180° to each other.

Do not award M3 if OH ---- C bond is represented.

formation of organic product 3-methylbutan-2-ol and Cl–; 4

(ii) OH– has a negative charge/higher electron density;

greater attraction to the carbon atom (with the partial positive

charge) / OWTTE; 2

Do not allow just greater attraction.[6]

22. CH3CH2CH2CH2Cl + KCN → CH3CH2CH2CH2CN + KCl;

Accept CN– for KCN and Cl– for KCl.

pentanenitrile;

Allow 1-cyanobutane.

CH3CH2CH2CH2CN + 2H2 → CH3CH2CH2CH2CH2NH2;

pentan-1-amine / 1-aminopentane / 1-pentylamine / 1-pentanamine;

Catalyst: nickel/Ni / palladium/Pd / platinum/Pt; 5

Penalize missing hydrogen once only.[5]


23.

curly arrow going from lone pair on O in H2O to carbonyl C and curly

arrow going from C=O bond to O;

Do not allow curly arrow originating on H in H2O.

representation of intermediate anion showing negative charge on

O and + on O of H2O;

Lone pair on O not required on representation of intermediate.

curly arrow going from lone pair/negative charge on O to C–O to form

C=O and curly arrow showing Cl leaving and curly arrow from H–O

bond to O+;

formation of organic product H3CCOOH and Cl– and H+/HCl; 4

[4]

24. (a)

curly arrow going from delocalized electrons in benzene to Cl in Cl2and curly arrow going from Cl–Cl bond to AlCl3;

Allow curly arrow going from delocalized electrons in benzene to Cl+ for M1.

representation of carbocation with correct formula and positive charge on ring;

curly arrow going from lone pair/negative charge on Cl in AlCl4– to H and

curly arrow going from CH bond to benzene ring;

formation of organic product chlorobenzene and HCl and AlCl3; 4

Allow other suitable catalysts such as FeCl3 etc.

Allow mechanism with corresponding Kekulé structures.

(b) methylbenzene more reactive / nitrobenzene less reactive;

methyl group electron donating and nitro group electron withdrawing; 2[62]


25. B[1]

26. D[1]

27. D[1]

28. C[1]

29. (i) addition of bromine/bromine water;

the bromine colour remains with propane and propene

decolourizes the bromine / solution changes from brown to colourless; 2

Do not accept “clear” instead of “colourless”.

(ii) addition (polymerization);

( CH(CH3)–CH2 ) / –CH(CH3)CH2–; 2

Continuation bonds necessary for mark, displayed formula or

condensed structural formula can be given.

Accept if more than one repeating unit is shown.

(iii) hydrogenation (of vegetable oils) / manufacture of margarine /

manufacture of ethanol / addition of water; 1

Accept manufacture of alcohol.

Do not accept hydrogenation of alkenes.[6]

30. (i) C3H8O + 4

O2 → 3CO2 + 4H2O / 2C3H8O + 9O2 → 6CO2 + 8H2O 22

1

Award [1] for correct products and reactants and [1] for correct

balancing.

Ignore state symbols.

(ii) acidic solution / H+ / sulfuric acid;

warm / heat / reflux;

(the solution changes) from orange to green; 3


(iii) CH3CH2CHO and propanal;

CH3CH2COOH and propanoic acid;

CH3COCH3 and propanone/acetone;

Award [1] for 2 or 3 correct names or structures, award [2] for

4 or 5 correct names or structures.

propan-1-ol gives propanal and propanoic acid and propan-2-ol

gives propanone;

propan-1-ol has two H atoms bonded to the C containing the

–OH whereas propan-2-ol only has one / propan-1-ol is a primary

alcohol and propan-2-ol is a secondary alcohol; 5[10]

31. (a) 1,3-cyclohexadiene; 1

(b) addition reactions not favoured energetically since this would

involve disruption of cloud of delocalized electrons / stabilization

energy would need to be supplied and product would lack

delocalized ring of electrons making it less stable / OWTTE; 1[2]

32. For chloromethylbenzene:

electron deficient carbon on –CH2Cl group making it susceptible to

nucleophilic attack;

For chlorobenzene:

steric hinderance / repulsion by electron cloud in benzene ring/C–Cl less polar;

C–Cl bond stronger; 2 max

Award [1] mark for either of the above.[2]

33. (a) (i) H3CCHClCH2I ; 1

(ii) H3CC(OH)(CN)H; 1


(iii)

1

(iv) (CH3)2CHOH ; 1

(b) CH3CHICH2Cl ; 1

(c)

Reaction Type

(a) (i) electrophilic addition;

(a) (ii) nucleophilic addition;

(a) (iii) addition-elimination;

(a) (iv) Grignard;

4[9]


34. Catalyst:

(concentrated) H3PO4/phosphoric acid/H2SO4/sulfuric acid;

Mechanism:

curly arrow going from O of OH to H+ (showing protonation of OH group)

and loss of water showing formation of carbocation;

curly arrow from CH of beta-carbon to CC;

Organic product:

ethene; 4

Accept ethylene.[4]

35. Step 1:

H3PO4 /phosphoric acid / H2SO4 /sulfuric acid;

Product from step 1:

CH3CH2CH=CH2 /but-1-ene;

Step 2:

Br2 /bromine; 3

[3]

36. B[1]

37. C[1]


38. A[1]

39. B[1]

40. (a)

correct isomer 3D structure; 3

correct name;

correct enantiomer 3D structure;

If compound incorrectly named award [2 max] for two correct 3D

enantiomers, and [1 max] for a correct structure of an enantiomer not

shown in 3D.

If non-optically active isomers given (e.g. 2-bromo-2-methyl-butane)

award [1 max] if name and 3D structure are correct.

Accept condensed form for alkyl chain throughout.


(b) (i)

curly arrow going from lone pair/negative charge on O in

HO– to C bonded to Br;

Do not allow curly arrow originating on H in HO– (e.g. originating

on negative charge on H, i.e. lone pair/negative charge must be on O).

curly arrow from C–Br bond to form Br– (this can also be

shown in transition state);

transition state showing overall negative charge; 3

Accept condensed formulas as long as curly arrows can

still be shown, e.g.

If wrong formula used for halogenoalkane, e.g. 1-bromobutane

award [2 max].


(ii)

curly arrow from C–Br bond to form Br–;

correct structure of tertiary carbocation;

curly arrow going from lone pair/negative charge on O

in HO– to C+; 3

If non-bonding pair not shown then arrow must originate from

negative sign on O or the minus sign.

Only penalize arrow from H once in (b).

If wrong formula is used for 2-bromo-2-methylbutane

award [2 max].

(iii) the C bonded to the Br in 1-bromopentane is also bonded

to two H atoms so can accommodate five groups around it

in the transition state / OWTTE;

the C bonded to the Br in 2-bromo-2-methylbutane has

three other (bulky) groups bonded to it so cannot

accommodate five groups around it in the transition state /

OWTTE;

2-bromo-2-methylbutane forms a tertiary carbocation

which is stabilized by the positive inductive effect of the

three alkyl groups / OWTTE;

1-bromopentane would form a primary carbocation (if it

went by SN2) which is much less stable as there is only

one alkyl group exerting a positive inductive effect / OWTTE; 3 max

(iv) the boiling point of 1-bromopentane is higher than the

boiling point of 2-bromo-2-methylbutane;

2-bromo-2-methylbutane is more spherical in shape / less

surface area in contact between molecules of 2-bromo-

2-methylbutane than between molecules of 1-bromopentane /

OWTTE;

hence weaker intermolecular forces of attraction/van der

Waals’ forces of attraction between molecules of 2-bromo-

2-methylbutane / OWTTE; 3

(v) esterification / condensation;

CH3–CO–O–(CH2)4CH3 / CH3COO(CH2)4CH3 /

CH3COOCH2CH2CH2CH2CH3 /

2

Accept CH3–CO–O–C5H11


(c) elimination;

neither can exist as geometrical isomers as they contain the

same two groups/atoms on one of the double bonded carbon

atoms / OWTTE; 4[21]

41. (i) nHO–(CH2)5–OH + nHOOC–C6H4–COOH

→ H–[O–(CH2)5–O–CO–C6H4–CO–]n–OH + (2n – 1)H2O 3

Award [1] for correct reactants, [1] for correct polyester and

[1] for balanced water.

Award [3] if correct equation given for one molecule of diol

reacting with one molecule of dicarboxylic acid.

i.e.

HO–(CH2)5–OH + HOOC–C6H4–COOH → HO–(CH2)5–O–CO–C6H4–COOH + H2O

(ii) formation of polyesters/condensation polymers/synthetic fabrics; 1[4]

42. (a) (i) CH3CONHCH2CH3 and HCl; 1

Allow corresponding names also.

(ii) 2-nitromethylbenzene and 4-nitromethylbenzene /

1

Allow use of ortho and para notation.


(b)

curly arrow from ring to +NO2 electrophile;

drawing of intermediate structure with + on ring;

curly arrow from C–H to +; 3

Allow corresponding mechanism for formation of para isomer.

Allow corresponding mechanism involving Kekulé notation.[5]

43.

formation of CH3CO+ electrophile;

curly arrow from ring to CH3CO+ electrophile;

curly arrow from CH to + in ring;

formation of C6H5COCH3 and H+ ; 4

Allow corresponding mechanism involving Kekulé notation.[4]

44. D[1]

45. B[1]

46. B[1]


47. A[1]

48. (i)

Accept lines, dots or crosses for electron pairs.

Lone pairs required on chlorine.

(approximately)120°;

Accept any bond angle in the range 113–120°. 2

(ii)

Brackets not required for mark.

Allow correct condensed structural formula.

Continuation bonds from each carbon are required.

Cl atoms can be above or below carbon spine or alternating

above and below. 1

(iii) plastics are cheap/versatile/a large industry / plastics have

many uses / OWTTE;

plastics are not biodegradeable / plastics take up large amounts of space in

landfill / pollution caused by burning of plastics / OWTTE;

Do not accept plastics cause litter.

Allow plastics don’t decompose quickly / OWTTE. 2[5]

49. (i) Step 1:

CH2CHCl + H2 → CH3CH2Cl;

Step 2:

CH3CH2Cl + OH– → CH3CH2OH + Cl–;

Allow NaOH or NaCl etc. instead of OH– and Cl–.

Allow abbreviated formulas C2H3Cl, C2H5Cl, C2H5OH. 2


(ii) H2SO4/H+/acidified and Cr2O72–/(potassium/sodium) dichromate;

Accept suitable oxidizing agents (e.g. KMnO4 etc.) but only with acid.

Ignore missing or incorrect oxidation states in reagents.

(heat under) reflux;

Second mark can be scored even if reagent is incorrect. 2

(iii) CH3COOH(aq) + H2O(l) CH3COO–(aq) + H3O+(aq)

OR

CH3COOH(l) + H2O(l) CH3COO–(aq) + H3O+ (aq)

OR

CH3COOH(aq) CH3COO–(aq) + H+(aq)

correct equation;

state symbols and ;

BL acid is CH3COOH and cb is CH3COO– / BL acid is H3O+ and cb is H2O; 3

[7]

50. same general formula;

same functional group;

successive members differ by CH2;

Allow methylene for CH2.

similar chemical properties;

gradually changing physical properties; 2 max[2]

51. (a) (i) A: butan-1-ol;

B: butan-2-ol;

C: (2-)methylpropan-2-ol;

D: (2-)methylpropan-1-ol;

Accept answers in the form of 1-butanol and 2-methyl-2-propanol etc.

Penalize incorrect punctuation, e.g. commas for hyphens, only once. 4

(ii) C/(2-)methylpropan-2-ol; 1

(iii) A/butan-1-ol; 1

(iv) B/butan-2-ol; 1


(v)

1

(b) (i) SN2; 1

(ii)

curly arrow going from lone pair/negative charge on O in OH– to C;

Do not allow curly arrow originating on H in OH–.

curly arrow showing Br leaving;

Accept curly arrow either going from bond between C and Br to Br in

1-bromobutane or in the transition state.



Do not penalize if HO and Br are not at 180° to each other.

Do not award third mark if OH----C bond is represented. 3[12]

52. (a) C2H5MgBr + H2O → C2H6 + Mg(OH)Br

Award [1] for C2H6 and [1] for correct equation. 2


(b) (i) butan-2-ol/2-butanol;

CH3CH2CH(OH)CH3; 2

(ii) 2-methylbutan-2-ol;

C2H5C(CH3)2OH; 2

[6]

53. (i) but-1-ene/1-butene; 1

(ii)

curly arrow going from lone pair on O to H+;

representation of positively charged O intermediate and curly arrow

showing H2O leaving;

curly arrow going from lone pair on O of H2O/H2PO4– to H and curly

arrow going from CH bond to C–C+ to form C=C;

No mark awarded if C+ is not represented. 3[4]

54. (a) as the bromine approaches the alkene an induced dipole is formed / OWTTE; 1

(b) (i) 2,3-dibromobutane; 1


(ii) 2-bromobutane; 1[3]

55.

showing curly arrow from double bond to H (in H–Br) and curly arrow from bond in

H–Br to Br;

showing the curly arrow from the lone pair/negative charge on Br– to the secondary

carbocation and 2-bromobutane as correct product;

stating that the secondary carbocation will be formed in preference to the primary

carbocation;

the two positive/electron releasing inductive effects due to the two R– groups on the

secondary carbocation make it more stable; 4[4]

56. (a) the C–C bond lengths are all the same;

IR absorption of C–C bonds in benzene is different to that of both C–C

single bonds and C=C double bonds;

chemical shift of protons in benzene is different to that of protons in alkenes;

only one isomer exists for 1,2-disubstituted benzene compounds;

Do not accept average bond enthalpy in benzene is between

that of C–C and C=C. 2 max

(b) substitution rather than addition occurs / bromine is not

decolourized (without a catalyst)/OWTTE; 1[3]


57. D[1]

58. A[1]

59. D[1]

60. C[1]

61. (a) A: l-bromobutane;

B: 2-bromobutane;

C: 2-bromo-2-methylpropane;

D: 1-bromo-2-methylpropane;

Penalize incorrect punctuation, e.g. commas for hyphens, only once.

Accept 2-bromomethylpropane and 1-bromomethylpropane for

C and D respectively. 4

(b) (i) C/2-bromo-2-methylpropane;

unimolecular nucleophilic substitution; 2

(ii) RBr → R+ + Br–;

Allow use of 2-bromo-2-methylpropane instead of RBr. 1


(iii) A/1-bromobutane/D/1-bromo-2-methylpropane;





1-bromobutane or in the transition state.




Do not award fourth mark if OH----C bond is represented. 4

(c) (b)(i) no change as [OH–] does not appear in rate equation/in

the rate determining step;

(b) (iii) rate doubles as the rate is proportional to [OH–] / OH–

appears in the rate-determining/slow step / first order with

respect to OH–;

Award [1] if correctly predicts no rate change for SN1 and

doubling of rate for SN2 of without suitable explanation. 2

(d) rate of 1-bromobutane is faster;

C–Br bond is weaker/breaks more easily than C–Cl bond; 2

(e) 2-bromobutane/B;

(plane-) polarized light shone through;

enantiomers rotate plane of plane-polarized light to left or right/

opposite directions (by same amount);

Accept “turn” instead of “rotate” but not “bend/reflect”.

physical properties identical (apart from effect on plane-polarized light);

chemical properties are identical (except with other chiral compounds);

Do not accept “similar” in place of “identical”. 5

(f) (i) elimination; 1


(ii)

curly arrow going from lone pair/negative charge on O in OH– to H on β-C;


Allow C2H5O– instead of OH–.

curly arrow going from CH bond to form C=C bond;


Accept the following for first 3 marks.


representation of carbocation;

curly arrow going from lone pair/negative charge on O in OH–

to H on C adjacent to C+ and curly arrow going from

CH bond to form C=C bond;

two products formed: but-1-ene / but-2-ene/(cis) but-2-ene/

(trans) but-2-ene;

Award [1] for two correct answers. 4 max[25]


62. LDPE: free radical mechanism;

HLPE: use of a Ziegler-Natta catalyst / ionic mechanism / coordination

polymerization; 2[2]

63. aluminium chloride / iodide / iron chloride;

Accept AlCl3 / AlI3 / FeCl3.

showing curly arrows from benzene ring to CH3– and curly arrow from bond in

CH3–I to catalyst;

Accept prior formation of electrophile to give CH3+ and AlICl3

–/AlI4–.

correctly showing intermediate;

Accept mechanism with corresponding Kekulé structures.

curly arrow from –H into ring and curly arrow from catalyst anion to H; 4[4]

64. (i) 1-methyl-2-nitrobenzene and 1-methyl-4-nitrobenzene;

Accept 2-methylnitrobenzene and 4-methylnitrobenzene.

Accept 2-nitromethylbenzene and 4-nitromethylbenzene.

Accept o-methylnitrobenzene and p-methylnitrobenzene. 1

(ii) NO2+ / nitronium ion;

the (concentrated) sulfuric acid protonates the nitric acid /

HNO3 + H2SO4 → H2NO3+ + HSO4

–;

the H2NO3+ formed loses water / H2NO3

+ → H2O + NO2+;

Accept HNO3 + H2SO4 → NO2+ + H2O + HSO4

– for the second

and third points. 3[4]

65. B[1]

and p-methylnitrobenzene. 1


(ii) NO2+ / nitronium ion;

the (concentrated) sulfuric acid protonates the nitric acid /

HNO3 + H2SO4 → H2NO3+ + HSO4

–;

the H2NO3+ formed loses water / H2NO3

+ → H2O + NO2+;

Accept HNO3 + H2SO4 → NO2+ + H2O + HSO4

– for the second

and third points. 3[4]

66. A[1]

67. B[1]

68. (i) colour change from yellow/orange/rust colour/red/brown to colourless;

No mark for change to clear, or for decolourized with no reference

to original colour. 1

(ii) Chloroethene:

No mark if the lone pairs missing on Cl.

Accept lines, dots or crosses for e– pairs.

Poly(chloroethene):

;

n and square brackets are not required.

Continuation bonds must be shown. 2

(iii) (hydration of ethene for the manufacture of) ethanol/ C2H4 + H2O → C2H5OH;

(synthesis of) CH3COOH /ethanoic/acetic acid;

(synthesis of) ethylene glycol/1,2-ethanediol/ethane-1,2-diol;

(synthesis of) drugs/pesticides;

(hydrogenation of unsaturated oils in the manufacture of) margarine;

Accept other commercial applications. 2 max[5]


69. (i)

Penalize missing H atoms once only. 2

(ii) CH3CH=CHCH3 + H2O → CH3CH(OH)CH2CH3;

concentrated sulphuric acid/ H2SO4 and heat/steam / phosphoric acid/H3PO4

(catalyst) and heat/steam;

3CH3CH(OH)CH2CH3 + Cr2O72– + 8H+ → 3CH3COCH2CH3 + 2Cr3+ + 7H2O;

Accept CH3CH(OH)CH2CH3 + [O] → CH3COCH2CH3 + H2O .

Accept C2H5 as CH2CH3.

dichromate(VI) (ion)/Cr2O72– and acidic/H+;

Accept MnO4– in place of Cr2O7

2– in third and fourth marks.

heat/reflux; 5[7]

70. (i) CH3CH2CH2OH, propan-1-ol/1-propanol;

CH3CH(OH)CH , propan-2-ol/2-propanol;

Need both formula and name for mark.

Accept either condensed or full structural formulas.

CH3CH2CH2OH: primary and CH3CH(OH)CH3: secondary; 3

(ii) CH3CH2CHO;

CH3CH2COOH;

CH3COCH3;

Accept either condensed or full structural formulas.

from propan-1-ol: CH3CH2CHO(propanal) obtained by distillation (as

product is formed);

propan-1-ol gives CH3CH2COOH (propanoic acid) by (heating under) reflux;

Award [1] if CH3CH2CHO and CH3CH2COOH identified but conditions

not given/incorrect.

propan-2-ol gives CH3COCH3 by heat / reflux; 5 max

[8]


71.

Allow ECF if major and minor products are interchanged.

Allow more detailed formulas throughout the option. 4[4]


72.

curly arrow showing movement of electron pair from the double bond to

hydrogen in HBr;

formation of Br–;

OR

equation for HBr dissociation;

curly arrow showing movement of electron pair from the double bond to H+;

correct structures of both carbocations;

curly arrow showing either C–Br bond formation / mechanism for either product;

Award [3 max] for mechanism.

(CH3)2CH+ is more stable / CH3CH2CH2+ is less stable; 4 max

[4]

73.

correct formulas of the reactants and the inorganic product;

correct formula of the organic product; 2[2]


74. Step 1:

CH3CH2CH2CH2OH CH3CH2CH=CH2 + H2O; →

+heat ,H

Accept H+, concentrated H3PO4 or concentrated H2SO4 as catalyst.

Reaction type for Step 1:

elimination/E / dehydration;

Step 2:

CH3CH2CH=CH2 + Br2 → CH3CH2CHBrCH2Br;

Reaction type for Step 2:

electrophilic addition/ AE;

Allow more detailed formulas. 5[5]

75. (a) increases acidity / OWTTE;

halogens are electron acceptors / halogens withdraw/pull electrons /

halogens are more electronegative than carbon;

(acceptors) increase O–H bond polarity / increase δ+ on H / decrease

O–H bond strength / favour dissociation of O–H bond / OWTTE;

increases the stability of the conjugate ion; 3 max

(b) chloroethanoic acid > 3-chloropropanoic acid > propanoic acid / OWTTE; 1

(c) any pKa value or range of values within the range 2.87– 4.86;

The actual pKa value is 3.98. 1

[5]

76. A[1]

77. A[1]

78. B[1]


79. B[1]

80. (a) compounds with same structural formula;

Do not allow “same molecular or chemical formula without the

same structural formula”.

but different arrangement of atoms in space/spatial arrangement; 2

(b) (i)

Cis(-1,3-dichlorocyclobutane)

Trans(-1,3-dichlorocyclobutane)

Need clear cis/trans structure and name for each mark.

Award [1] for 2 correct structures without names. 2

(ii) cis (higher boiling point);

cis (more) polar / trans non-polar/less polar;

cis experiences stronger (permanent) dipole-dipole interaction / trans

experiences no/(much) less dipole-dipole interaction;

Do not accept just strong forces without reference to

dipole-dipole interaction. 3[7]

81. (i)

Accept CH3CH2CH2Br. Accept CH3CH2CH2CH2NH2.

Penalize missing H atoms. 1


(ii) CH3CH2CH2Br + KCN → CH3CH2CH2CN + KBr;

Accept ionic equation.

CH3CH2CH2CN + 2H2 → CH3CH2CH2CH2NH2;

Equation must be balanced for mark.

Accept LiAlH4 in place of reaction with hydrogen.

For the second equation:

Ni (as catalyst);

heat/150 °C; 4[5]

82. (i) hot;

alcoholic OH– /NaOH/KOH;

C2H5Br + C2H5ONa → C2H4 + NaBr + C2H5OH /

C2H5Br + NaOH → C2H4 + NaBr + H2O;

Accept ionic equation with C2H5O– or OH–. 3


(ii) OH– reacts with ethanol to form ethoxide ion/C2H5OH + OH– → C2H5O– + H2O;

curly arrow going from lone pair/negative charge on O in C2H5O– /CH3CH2O– to

H on β–C;

Accept arrow origin from OH– but do not allow curly arrow

originating on H in OH–.

Accept OH– in place of C2H5O–(to form H2O).

curly arrow going from CH bond to form C=C bond;


structural formula of organic product CH2=CH2;

Award [4 max] for E1 mechanism (unstable primary carbocation)


representation of primary carbocation;

curly arrow going from lone pair on O in H2O to H on C

adjacent to C+ and curly arrow going from CH bond to

form C=C bond;

structural formula of organic product CH2=CH2; 5

[8]

83. (a)

Accept C6H6 and C6H5CH3 instead of their structural formulas.

Equilibrium sign and Lewis acid not required for mark.

Accept other workable Lewis acids e.g. FeCl3. 1


(b)

curly arrow going from delocalized electrons in benzene to +CH3;

Do not penalize if CH3+ is written.

representation of carbocation with correct formula and positive

charge on ring;

curly arrow going from lone pair/negative charge on Cl in AlCl4– to

H and curly arrow going from CH bond to benzene ring;

formation of organic product methylbenzene and HCl and AlCl3;

Allow mechanism with corresponding Kekulé structures. 4[5]

84. (a)

correct structural formulas of reactants, condensed or displayed;

correct structural formula, condensed or displayed, of

(4-methylphenyl)ethanone;

Accept 2-methyl isomer. 2

(b) sterical hindrance of the methyl group / CH3 is bulky enough to prevent

substitution at 2- and 6-positions / OWTTE;

CH3 is a (weakly) electron-releasing/Type I substituent / directs

substitution to 2-, 4- and 6-positions / stabilizes σ-complexes with

sp3 hybrid carbon in ortho- and para- positions / OWTTE;

CH3CO is an electron-withdrawing/deactivating/Type II substituent

(which) prevents/decreases the rate of further substitution / OWTTE; 2 max[4]


85.

correct structural formula of acetylsalicylic acid;

correct structural formula of ethanoic acid;

Accept condensed formula for ethanoic acid.

addition-elimination / condensation / esterification / nucleophilic substitution; 3[3]

86. B[1]

87. A[1]

88. C[1]

89. B[1]

90. (a) methylpropene;

Accept 2-methylpropene. 1

(b) (i) brown/orange/yellow to colourless / bromine is decolorized; 1


(ii) 1,2-dibromo-2-methylpropane / 1,2-dibromomethylpropane / 1-bromo-2-

methylpropan-2-ol / 1-bromomethylpropan-2-ol;

Do not penalize missing commas, hyphens or added spaces.

Award [1] if structure and correct name are given for 2-bromo-2-

methylpropan-1-ol. 2[4]

91. (i) synthesis of materials not naturally available/plastics;

chemically unreactive materials produced;

wide range of uses/physical properties / versatile;

cheap;

large industry;

uses a limited natural resource;

Award [2] for any two. 2 max

(ii) addition; 1

(iii)

Must show continuation bonds.

Ignore bracket around the 6 carbons.

Must have 6 carbons joined to each other along chain. 1

(iv) monomers are smaller molecules / have smaller surface area than polymers;

Accept monomers have lower molecular mass.

with weaker intermolecular/Van der Waals’/London/dispersion forces;

Accept opposite argument for polymers. 2[6]

92. chloroethane;

(electrophilic) addition;

Do not accept free radical/nucleophilic addition. 2[2]


93. (a) nC =

= 6.80 and nH =

= 18.1;01.12

7.81

01.1

3.18

ratio of 1: 2.67 /1: 2.7;

C3H8;

No penalty for using 12 and 1. 3

(b) C3H8; 1

(c) (i) Br2 /bromine;

UV/ultraviolet light;

Accept hf/hv/sunlight. 2

(ii) Cr2O72– /MnO4

– and acidified/ H+ /H3O+;

Accept names.

heat / reflux; 2

(d) Initiation:

Br2 → 2Br•;

Propagation:

Br• + RCH3 → HBr + RCH2•;

RCH2• + Br2 → RCH2Br + Br•;

Termination: [1 max]

Br• + Br• → Br2;

RCH2• + Br• → RCH2Br;

RCH2• + RCH2• → RCH2CH2R;

Award [1] for any termination step.

Accept radical with or without • throughout.

Do not penalize the use of an incorrect alkane in the mechanism. 4 max

(e) (i) substitution and nucleophilic and bimolecular/two species in

rate-determining step;

Allow second order in place of bimolecular. 1


(ii)


Do not allow curly arrow originating on H in OH–



bromoethane or in the transition state.




Do not award M3 if OH ---- C bond is represented unless already

penalized in M1.

Do not penalize the use of an incorrect alkyl chain in the mechanism. 3[16]

94. (i) CH3OCH2CH;

CH3CHOHCH;

Allow more detailed structural formulas. 2

(ii) CH3CHOHCH3 has higher boiling point due to hydrogen bonding;

CH3OCH2CH3 has lower boiling point due to Van der Waals’/London/

dispersion/dipole-dipole forces;

hydrogen bonds in CH3CHOHCH are stronger;

Allow ecf if wrong structures suggested. 2 max[4]

95. (a) hexagonal / ring of six carbon atoms (each with one hydrogen);

planar;

all carbon-carbon bond lengths equivalent / all carbon-carbon bond lengths

intermediate between single and double bonds / carbon-carbon bond

order of 1.5;

all C–C–C bond angles 120°;

Allow sp2 (hybridization for Cs).

delocalization / resonance; 3 max


(b) enthalpy change of hydrogenation not equal to three times enthalpy

change of hydrogenation of cyclohexene;

electron density map (of benzene) showing equal electron density/all

carbon-carbon bond lengths equivalent / OWTTE;

Allow diffraction pattern or contour map for electron density map.

only one isomer exists for 1,2-disubstituted benzene compounds /

only three disubstituted benzene compounds (rather than four);

undergoes (electrophilic) substitution reactions / does not undergo

addition reactions / does not decolorize bromine water; 2 max[5]

96. (a) A: CH3CH2CH(CH3)Br; 1

(b)

1[2]

97. (addition of) Mg/magnesium;

CH3CH2CH2MgBr;

(addition of) CO2/carbon dioxide and H2O/water;

CH3CH2CH2CO2H / CH3CH2CH2COOH; 4

[4]

98. concentrated phosphoric acid/ H3PO4 /sulfuric acid/ H2SO4;

(CH3)CH=CH2;

Br2 /bromine;

BrCH2CHBrCH3; 4

[4]

99. (a) phenol;

negative charge/lone pair on oxygen can interact with delocalized

electrons of benzene/aromatic ring so spreads out charge more / OWTTE; 2


(b) chloroethanoic acid;

chlorine (atoms) withdraws electrons from OH bond, making it

break more easily to release H+ ions / electron-withdrawing nature

of chlorine / greater electronegativity of chlorine / OWTTE;

ClCH2CO2– more stable than CH3CO2

– because negative charge

spread more / OWTTE; 3[5]

100. D[1]

101. B[1]

102. B[1]

103. C[1]

104. (a)

First and second structures should be mirror images.

Tetrahedral arrangement around carbon must be shown. 2

(b) (i) order with respect to OH– = 0;

order with respect to X = 1;

rate = k[X];

Award [3] for final correct answer. 3


(ii) 0.2(0);

min–1; 2

(iii) 2-bromo-2-methyl-propane;

Do not penalize missing hyphens or added spaces.

Accept 2-bromomethylpropane.

tertiary (structure); 2

(iv) C4H9Br → C4H9+ + Br– / in equation with curly arrows and slow;

C4H9+ + OH– → C4H9OH / in equation with curly arrows and fast;

No penalty if primary structure is shown.

No credit for SN2 mechanism, except by ECF. 2

[11]

105.

curly arrow going from delocalized electrons in benzene to Cl in Cl2 and curly

arrow going from Cl–Cl bond to AlCl3;

Do not penalize if curly arrow originates inside circle.

Allow curly arrow going from delocalized electrons in benzene to Cl+ for M1.

representation of carbocation with correct formula and positive charge on ring;

curly arrow going from lone pair/negative charge on Cl in AlCl4– to H and curly

arrow going from CH bond to benzene ring;

Allow H+ + AlCl4– → HCl + AlCl3 as alternative to curly arrow going from lone

pair/negative charge on Cl in AlCl4– to H.

formation of organic product chlorobenzene and HCl and AlCl3;

Allow other suitable catalysts such as FeCl3 etc.

Allow mechanism with corresponding Kekulé structures. 4[4]


106. (addition of) Br2 / bromine and UV light/hf/hv;

(addition of) Br2 / bromine and AlBr3 / aluminium bromide / AlCl3

aluminium chloride;

Allow other suitable catalysts such as FeBr3 etc.

structure of first product

i.e.

Order of steps does not matter (so first product could form 2-bromomethylbenzene). 3[3]

107. (a) CH3CONHCH2CH3;

CH3CH2NH3+Cl– /CH3CH2NH3Cl;

Order of E and F does not matter. 2

(b) CH3CH2NH2 / ethylamine; 1

(c) addition-elimination;

Accept acylation. 1[4]

108. A[1]

109. C[1]

110. C[1]

111. A[1]


112. (i) butane < propanal < propan-1-ol;

butane has van der Waals’/London/dispersion forces;

propanal has dipole-dipole attractive forces;

propan-1-ol has hydrogen bonding;

imf marks are independent of the order.

Treat references to bond breaking as contradictions if the imfs are correct. 4

(ii) butane is least soluble;

it cannot form hydrogen bonds/attractive forces with water molecules; 2

(iii) propanal and propanoic acid;

3

(iv)

1

(v) secondary (alcohol);

propanone / acetone; 2[12]

113. (i) hydrogen bromide / hydrobromic acid;

Do not accept HBr, as name is asked for. 1

(ii) sodium hydroxide / hydroxide ions (name required);

dilute and aqueous / dilute and warm / aqueous and warm; 2


(iii)

curly arrow from OH– to C atom;

Accept from lone pair or minus sign or O. Do not award marking point if

arrow originates from the H of OH–.

curly arrow from bond between C and Br to bromine atom on bromoethane

or the transition state;

transition state including negative charge and partial bonds; 3

(iv) hydration of ethene / steam + ethene;

Allow equation

(ethanol used as) solvent/fuel/antiseptic/intermediate to form

other compounds; 2[8]

114. (a) contains a six-membered carbon ring;

all C–C bond distances are equal/0.139 nm;

C–C bond lengths are intermediate between single (0.154 nm)

and double bonds (0.134 nm) / has delocalized electrons /

drawing showing two resonance forms e.g.

planar;

all bond angles are 120°/the same;

Accept all carbons are sp2 hybridization. 4 max

(b) (THO =) –360 (kJ mol–1); 1[5]


115. (i)

SN(2)/nucleophilic substitution (bimolecular); 2

(ii) OH– ions repelled by the delocalized electrons in aromatic ring / OWTTE;

C–Br bond is stronger/harder to break because lone pair of electrons on Br

interact with delocalized electrons / OWTTE; 2[4]

116. (i) CH3MgBr/methyl magnesium bromide; 1

(ii)

Allow correct condensed structural formula in each case

e.g. CH3CH2COOH etc. 2

[3]


117.

Allow correct condensed structural formula in each case.

Do not penalize students if they draw a structure that attaches NO2 to benzene ring

via O and not N, also students do not have to show double and triple bonds. 4[4]


118.

correct identification of products as (CH3)2C=CH2/methylpropene;

mechanism showing:

curly arrow going from (lone pair of electrons on) O to H+;

structure of carbocation;

curly arrow from (lone pair on) oxygen of water to H shown;

Award [3] for a concerted mechanism.

Correct geometry is not required for structure of carbocation. 4[4]

119. C[1]

120. D[1]

121. B[1]


122. B[1]

123. D[1]

124. (a) (i) CH3CH2CH2Br → CH3CH2CH=CH2 + HBr /

CH3CH2CH2CH2Br + OH– → CH3CH2CH=CH2 + H2O + Br–;

alcoholic NaOH/OH–;

reflux / heat;

Penalize missing Hs once only throughout the question 3

(ii) elimination reaction;

Then accept either E1 or E2 mechanism.

E1

curly arrow showing bromine leaving the halogenoalkane;

OH– acting as base on the intermediate carbocation;

E2

curly arrow showing OH– acting as base on H bonded to C;

concerted curly arrows showing Br leaving C–Br; 3


(iii) CH3CH2CH2CH2Br + NH3 → CH3CH2CH2CH2NH2 + HBr;

ammonia/NH3;

warm / excess ammonia (to prevent secondary amines etc.); 3

(iv)

curly arrow from ammonia (to form transition state);

correct transition state;

curly arrow from bond to Br atom in either the first or second step;

formation of HBr and organic product;

Accept a second molecule of NH3 removing H+ from the transition state

to give NH4+ and Br– as products. 4

(b) (i)

Award [1] for correct structure and [1] for correct 3-D

representation of both enantiomers. 2

(ii) polarimeter (to measure angle of rotation);

the plane of plane-polarized light rotates in opposite directions

(by the different enantiomers); 2

(iii) 2-bromo-2-methylpropane is tertiary / 1-bromobutane is primary;

2-bromo-2-methylpropane goes by SN1 / 1-bromobutane by SN2;

intermediate carbocation more stable for tertiary;

no space around tertiary carbon for five groups (in SN2

transition state); 3 max[20]

125. (i) amide / peptide; 1

(ii) H2N(CH2)6NH2;

HOOC(CH2)8COOH / ClOC(CH2)8COCl; 2


(iii) nHOOCC6H4COOH + nHOCH2CH2OH

→ HO--(--OCC6H4COOCH2CH2O--)n–H + (2n – 1)H2O;

Award [1] for correct organic product and [1] for (2n – 1)H2O.

Accept --(--OCC6H4COOCH2CH2O--)n— for the organic product. 2

[5]

126. (i) HNO3 + 2H2SO4 → NO2+ + 2HSO4

– + H3O+ /

HNO3 + H2SO4 → NO2+ + H2O + HSO4

– / HNO3 + H2SO4 → H2NO3+ + HSO4

–

and H2NO3+ → H2O + NO2

+

Award [1] for correct reactions and products and [1] for balancing.

Also accept two step equations or curly arrow equations. 2


(ii)

equation showing the formation of the CH3CO+ ion;

curly arrow going from benzene to electrophile and subsequent formation

of intermediate correctly represented in mechanism;

curly arrow showing removal of proton and second curly arrow showing

the reformation of the aromatic ring to form the new product and

hydrogen chloride;

Award [1 max] for the equation:

3[5]


127.

correct reagents and first step;

Chlorobenzene is not necessary for mark.

first product;

reaction with Br2 and UV light in second step;

Accept correct names or condensed formulas in place of structures.

Accept other reasonable suggestions. 3[3]

128. (i) reaction with Br2 and UV light (to react with methyl group);

Br2 and AlBr3 / AlCl3 (to substitute in benzene ring);

Accept in either order. 2

(ii)

(nucleophilic) substitution only on alkyl group/nucleophilic substitution

cannot occur on benzene ring / OWTTE; 2[4]

129. D[1]

130. C[1]

131. A[1]


132. C[1]

133. (i) energy required to break (1 mol of) a bond in a gaseous molecule/state;

Accept energy released when (1 mol of) a bond is formed in a gaseous

molecule/state / enthalpy change when (1 mol of) bonds are made or

broken in the gaseous molecule/state.

average values obtained from a number of similar bonds/

compounds / OWTTE; 2

(ii) Bonds broken

(1)(C–C) + (1)(O–H) + (5)(C–H) + (1)(C–O) + (3)(O=O)

= (1)(347) + (1)(464) + (5)(413) + (1)(358) + (3)(498) = 4728(kJ);

Bonds formed

(2 × 2)(C=O) + (3 × 2)(O–H)

= (4)(746) + (6)(464) = 5768 (kJ);

TH = 4728 – 5768 = –1040 kJ mol–1 / –1040 kJ;

Units needed for last mark.

Award [3] for final correct answer.

Award [2] for +1040 kJ. 3

(iii) Mr(C2H5OH) = 46.08 / 46.1 and Mr(C8H18) = 114.26/114.3;

1 g ethanol produces 22.57 kJ and 1 g octane produces 47.88 kJ;

Accept values ranges of 22.5–23 and 47.8–48 kJ respectively.

No penalty for use of Mr = 46 and Mr = 114. 2

(iv) A: CH3CHO;

B: CH3COOH/CH3CO2H;

Accept either full or condensed structural formulas but not the

names or molecular formulas.

A: distillation;

B: reflux; 4

(v) ethanol/CH3CH2OH;

hydrogen bonding (in ethanol);

Award second point only if the first is obtained. 2

(vi) (concentrated) H3PO4 /(concentrated) phosphoric acid / H2SO4/sulfuric acid;

dyes / drugs / cosmetics / solvent / (used to make) esters / (used in)

esterification/disinfectant; 2[16]

134. (i) (2-)methylbutane / (2,2-)dimethylpropane; 1


(ii)

curly arrow going from O/lone pair of OH–(but not H) to the C attached to Br;

leaving of Br;

transition state representation with both Br and OH attached to C–1;

correct products CH3(CH2)4OH and Br–;

Charge must be shown for TS.

C–OH and C–Br bonds in TS must be represented by dashed lines. 4[5]

135. (a) bonding electron pair spread over three (or more) nuclei or atoms/

not restricted/confined between two nuclei or atoms / OWTTE; 1


(b) physical evidence [2 marks]:

same carbon–carbon bond lengths in benzene / all carbon–carbon bonds are

equal in length / forms regular hexagon;

instead of longer single bonds and shorter double bonds / intermediate

between single and double;

OR

3 isomers of C6H4X2;

not 4;

OR

not (structural) isomers / same compounds;

OR

(1H/proton) NMR spectrum shows only one peak / all the Hs in the

same chemical environment;

not 2 peaks / not 2 different chemical environments;

OR

electron density maps;

show even electron density over ring;

chemical evidence [2 marks]:

hydrogenation of C6H6 (1,3,5-cyclohexatriene) expected to

produce three times as much energy as cyclohexene;

benzene produces less (due to delocalization);

OR

benzene undergoes substitution rather than addition reactions;

as it is more stable (due to delocalization);

OR

enthalpy of combustion of C6H6 less than expected;

different bond energies; 4 max[5]


136. reaction is faster with C6H5CH2Cl;

C–Cl bond weaker/easier to break;

because no overlap between a lone electron pair of Cl with ring

delocalized electrons;

attacking OH– nucleophile not repelled by the delocalized electrons;

OR

reaction is slower with C6H5Cl;

C–Cl bond stronger/harder to break;

because of overlap between a lone electron pair of Cl with ring

delocalized electrons / delocalization increases electron density

on ring / delocalization reduces δ+ charge on C (attached to Cl atom);

attacking OH– nucleophile repelled by delocalized electrons / attraction of

nucleophile decreases / less polar C does not attract OH– as much; 3 max[3]

137. major product:

(CH3)2CBrCH2CH3/2-bromo-2-methylbutane;

minor product:

(CH3)2CHCHBrCH3/2-bromo-3-methylbutane;

mention of carbocation/(CH3)2C+CH2CH3/(CH3)2CHCH+CH3;

tertiary more stable than secondary carbocation / more alkyl groups with

positive inductive effect;

more electron releasing/pushing R/alkyl/C groups in tertiary; 5[5]

138.

Accept condensed structural formulas 2[2]


139. (a) reaction of Mg/magnesium with halogenoalkane/named compound;

in an anhydrous/dry solvent / (C2H5)2O /diethyl ether;

Accept equation with condition specified. 2

(b)

Accept either of the two following alternatives for the second

and third mark.

CH3COCH3;

C2H5MgBr;

OR

C2H5COCH3;

CH3MgBr;

If CH3COCH3 and CH3MgBr or C2H5COCH3 and C2H5MgBr

combination given, then award only [1]. 3 max[5]

140. B[1]

141. A[1]

142. C[1]

143. D[1]


144. A: CH3CHO;

B: CH3COOH/CH3CO2H;

Accept either full or condensed structural formulas but not the names

or molecular formulas.

A: distillation;

B: reflux; 4[4]

145. (concentrated) H2PO4/(concentrated) phosphoric acid / H2SO4/sulfuric acid;

dyes / drugs / cosmetics / solvent / (used to make) esters / (used in)

esterification / disinfectant; 2[2]

146. (i) CH3CH2OH CH3COOH CH3CH2CH2CH3 + H2O →722 OCrK

→OHCHCH

23

H+ H2SO4

Structural formulas of reactants and products

CH3CH2OH and CH3COOH/CH3CO2H and CH3CO2CH2CH3 (+ H2O);

Conditions/reagents used

reflux with named suitable acidified oxidizing agent and then heat with

alcohol and sulfuric acid;

Suitable oxidizing agents are potassium dichromate/K2Cr2O7 /

sodium dichromate/Na2Cr2O7 / dichromate/Cr2O72– / potassium

manganate(VII)/potassium permanganate/KMnO4 / permanganate/

manganate (VII)/MnO4–.

Accept H+/H2SO4 instead of sulfuric acid and acidified.

Award [1] for structural formulas of reactants and products and [1] for

the correct conditions/reagents used. 2


(ii) H2C=CH(CH3) CH3CH(OH)CH3 (CH3)2CO →OH

2 →

722 OCrK

H2SO4(conc.) H+

Structural formulas of reactants and products

H2C=CH(CH3) and CH3CH(OH)CH3 and (CH3)2CO;

Conditions/reagents used

water/H2O and sulfuric acid/H2SO4 / dilute acid medium and heat/reflux

with suitable acidified oxidizing agent;

Suitable oxidising agents are potassium dichromate/K2Cr2O7 / sodium

dichromate/Na2Cr2O7 / dichromate/Cr2O72– / potassium manganate(VII)/

potassium permanganate/KMnO4 / permanganate/manganate (VII)/MnO4–.

Accept H+/H2SO4 instead of acidified.

Note: If primary alcohol is given as product of first step, and everything

else correct, award [1 max].

Accept either full or condensed structural formulas throughout the question. 2[4]

147.

curly arrow going from O of –OCH2CH3 attacking hydrogen;

Allow the curly arrow to originate from either the lone pair or O of –OCH2CH3 but

not from H of –OCH2CH3.

Do not award first mark if curly arrow originates from O of NaOCH2CH3.

curly arrow going from the C–H bond on the β carbon to the bond joining the

α carbon to the β carbon and curly arrow showing Br acting as leaving group;

formation of (CH3)2C=CH2 and Br–;

Allow formation of NaBr for third marking point, if was used (incorrectly)

in the mechanism. Use of NaOCH2CH3 with curly arrow originating on

O of NaOCH2CH3 is penalized already in the first marking point.

Accept alternative E1 type mechanism

curly arrow showing Br acting as leaving group to form carbocation;

curly arrow going from O of –OCH2CH3 attacking hydrogen;

formation of (CH3)2C=CH2 and Br–;

No marks awarded if a substitution mechanism is given. 3[3]


148. (i) compounds with the same (molecular formula and) structural formula but

different arrangements of atoms in space / OWTTE; 1

(ii)

Allow [1 max] if structures are correct but arrangement of groups in space

does not clearly show the cis/ trans isomerism.

(iii)

Allow [1 max] if the structures are correct but it is not clear that they are

mirror images. 2[3]

149. 1-chloro-3-nitrobenzene / meta-chloronitrobenzene / m-nitrochlorobenzene /

3-chloro-1-nitrobenzene / 3-chloronitrobenzene / 1-nitro-3-chlorobenzene /

3-nitrophenylchloride;

NO2 electron withdrawing/attracting;

deactivates ring / reduces electron density on ring;

slower rate compared to benzene;

greater charge distribution in the 3-position / lesser charge in the 2- and 4-positions; 5[5]


150. CH3COCl + NaOH → CH3COOH + NaCl / CH3COCl + OH– → CH3COOH + Cl–;

addition–elimination mechanism;

movement of electrons from OH– to C, originating from negative charge or oxygen atom;

movement of electrons in the C=O;

Partial polarity on C=O and C–Cl not required for mark.

intermediate;

Curly arrows not required for mark. 5[5]

151. C[1]

152. A[1]

153. D[1]

¥ ì154. C[1]


155. (a) (i)

Isomer A B C

Boiling point 36 °C 28 °C 10 °C

Award [1] if correct boiling points are assigned to 3 isomers.

increase in branching / more side chains / more spherical shape /

reduced surface contact / less closely packed;

weaker intermolecular force/van der Waals’/London/dispersion forces;

Accept the opposite arguments 3

(ii) B: 2-methylbutane/methylbutane;

C: 2,2-dimethyl propane/dimethyl propane;

Do not penalize missing commas, hyphens or added spaces.

Do not accept 2-dimethylpropane, or 2,2-methylpropane. 2

(b) C5H12;

Accept any two of the following explanations.

C5H11OH has greater molar mass / produces less grams of CO2 and

H2O per gram of the compound / suitable calculations to show this;

C5H11OH contains an O atom which contributes nothing to the energy

released / partially oxidized / OWTTE;

analogous compounds such as butane and butan-1-ol show a lower

value for the alcohol per mole in the data book / OWTTE;

the total bond strength in the pentanol molecule is higher than the total

bond strength in pentane;

the total amount of energy produced in bond formation of the products

per mole is the same;

fewer moles of pentanol in 1 g;

pentanol requires more energy to break intermolecular forces/

hydrogen bonding / OWTTE; 3 max[8]

156. (i) C4H9Cl + KOH → C4H9OH + KCl; 1

(ii) (substitution)

nucleophilic;

unimolecular / OWTTE; 2

(iii) 1-chlorobutane:

SN2;

2-chloro-2-methylpropane:

SN1; 2


(iv) SN2 1-chlorobutane–allow ECF from (iii).

curly arrow going from lone pair or negative charge on O in OH– to C;

curly arrow for Cl leaving;

Can be shown in transition state.

formation of the transition state in bracket, with negative charge and dotted

lines to represent bonds;

SN1 2-chloro-2-methylpropane–allow ECF from (iii)

curly arrow showing Cl leaving;

formation of carbocation;

curly arrow from lone pair or negative charge on O in OH– to C+; 6[11]


157. (i)

Penalize missing H atoms once only.

Accept correct condensed structural formulas. 4

(ii) CH3–CH2–CH2–CHO / (CH3)2CHCHO;

CH3–CH2–CH2–COOH / (CH3)2CHCOOH; 2

(iii) CH3–CH2–CO–CH3; 1

(iv) orange to green; 1


(v)

1[9]

158. (a) dimethylamine / (CH3)2NH; 1

(b) methyl groups electron-donating/electron-releasing/ involve

positive inductive effect;

stabilization of positive ion / so dimethylamine contains an

N-atom that is more electron-rich;

more likely to attract/accept proton from water molecule;

No ECF from (a). 2 max[3]

159. electronegative/electron-withdrawing chlorine draws electrons away

from carboxylate/ COO–/CO2– (group) / attracts electrons in the OH

bond closer to oxygen;

making conjugate base weaker (and hence making the acid stronger) /

reduces electron density on oxygen / so making it easier for a proton to leave; 2[2]

160. CH3Cl + Mg → CH3MgCl;

CH3MgCl + CO2 CH3COOH + Mg(OH)Cl; →OH 2

H2O required for mark

OR

CH3Cl + NaCN → CH3CN + NaCl;

CH3CN + H2O + H3O+ → CH3COOH + NH4+;

Allow any other reasonable pathway. 2 max[2]

161. (a) (i) A: CH3CH2C(CH3)2OH; 1


(ii)

1

(b) addition-elimination / condensation; 1[3]

162.

curly arrow from C=C to H of HI and curly arrow showing iodide leaving;

structure of carbocation and iodide attacking carbocation from either lone pair or

negative charge;

Allow CH3C+HCH2CH3.

structure of CH3CHI(CH2CH3) as major organic product (C);

secondary/ 2° carbocation more stable than primary/1° carbocation;

because it is stabilized by a greater number of electron-releasing alkyl groups;

Award [3 max] for a correct mechanism involving the formation of the

1-iodo product. 5[5]


163.

curly arrow showing lone pair on oxygen attacking H+;

curly arrow showing departure of water;

Allow no charge on O.

Do not allow departure of OH–.

formula/structure of carbocation;

Allow condensed formula if + charge on correct C atom

curly arrow showing lone pair of oxygen on water attacking hydrogen / curly arrow

from C–H bond to form C=C / curly arrow showing H2PO42– removing hydrogen;

Product D: CH2=CH2;

Only penalize once for missing lone pair on O.

For M4, allow other alternatives such as H2PO42– ion removing H+ (which shows

its action as a catalyst) or simple loss of H+.

e.g.

5[5]


164. A[1]

165. C[1]

166. D[1]

167. B[1]

168. (i)

2

(ii) no rotation possible due to double bond/pi bond;

Accept hindered or restricted rotation. 1

(iii)

correct structural formula;

chiral carbon atom identified; 2[5]


169. (i) trans has the higher melting point;

trans isomer has (predominantly) intermolecular hydrogen bonding;

cis isomer has (predominantly) intramolecular hydrogen bonding; 3

(ii) cis isomer readily releases water (vapour forming a cyclic anhydride);

Accept opposite arguments for trans isomer. 1[4]

170. (i) SN2; 1

(ii)

curly arrow going from CN– to C;


Curly arrow may be represented on transition state.

representation of transition state, showing negative charge and dotted lines;

products; 4

(iii) CH3CH2CN + 2H2 → CH3CH2CH2NH2;

Ni / Pt / Pd; 2[6]

171. (i) CH3CH2Br + OH– → CH3CH2OH + Br–;

CH3CH2Br + OH– → CH2=CH2 + H2O + Br–;

Accept KOH and KBr in the balanced equations

dilute KOH compared to concentrated KOH;

aqueous KOH compared to ethanolic KOH;

warm/40–50 °C compared to hot/80-100 °C;

Accept any two reaction conditions. 4 max


(ii)

curly arrow from O to H;

curly arrow from C–H to C–C;


products CH2=CH2 + Br– + C2H5OH/H2O; 4

(iii) addition; 1[9]

172. E: CH3COCl and AlCl3;

F: HNO3 and H2SO4;

G: CH3Cl and AlCl3;

For M1 and M3 award [1 max] if CH3COCl is given for E and CH3Cl

is given for G only without AlCl3. 3

[3]

173. (i) activating; 1

(ii) 2,4 / ortho/o, para/p directing; 1

(iii) electron-withdrawing nature of –NO2 group;

so makes benzene ring less susceptible to attack by electrophiles; 2[4]

174. B[1]

175. C[1]


176. A[1]

177. B[1]

178. A[1]

179. (a) one general formula / same general formula;

differ by CH2;

similar chemical properties;

gradual change in physical properties; 1

Award [1] for any two of the above characteristics.

(b) ethanol lower / ethanoic acid higher;

due to larger mass of ethanoic acid/stronger van der Waals’/

London/dispersion forces;

due to stronger hydrogen bonding/2 hydrogen bonds per molecule; 2

Accept either answer for second mark.

(c)

2

Allow condensed structural formulas such as

CH3CH2CH2CH2OH.

Award [2] for all three correct isomers, [1] for any two correct

isomers.[5]


180. (i) (Empirical formula =) C8H8O3;

2

H

C

O

;

C

O

O

H

H

H

H

H

H

H

Allow double bonds on arene in alternate positions, or allow

delocalized representation (of pi electrons).

(ii) the bond at 0.1373 nm is a double bond and the bond at 0.1424 nm is a

single bond;

in CO2(g) both bonds are double bonds and would have a value

around 0.137 nm; 2

(iii) Ester;

Arene/benzene ring;

Alcohol; 2

Award [2] for any three correct, award [1] for any two correct.

Do not accept alkane as a type of functional group in this

molecule.[6]

181. (i) boiling point increases as the number of carbons increases / OWTTE;

Greater Mr and hence greater van der Waals’/London/dispersion

forces present; 2


(ii) CH4 + Cl2 CH3Cl + HCl; →light UV/hv

Do not award mark if hv/uv light is not given.

Initiation step:

Cl2 2Cl•; →light UV/hv

Do not award mark if hv/uv light is not given.

Penalize once only.

Propagation step:

CH4 + Cl• → CH3• + HCl;

CH3• + Cl2 → CH3Cl + Cl•;

Termination step:

Cl• + Cl• → Cl2 or Cl• + CH3• → CH3Cl or CH3• + CH3• → CH3CH3; 5

Allow fish-hook half-arrow representations i.e. use of .

Penalize use of full curly arrows once only.

Penalize missing dots on radicals once only.[7]

182. (i) A. = CH3(CH2)7CHO;

B. = CH3(CH2)7COOH/CH3(CH2)7CO2H;

C. = (CH3)3COH;

D. = (CH3)2CO;

E. = BrCH2CH2Br; 5

Allow correct structural formulas.

(ii) addition;

/-(CH2-CH2)3-/-(CH2)6-; 2

[7]

183. D[1]

184. B[1]


185. D[1]

186. C[1]

187. (a)

Cl Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

and 1,1 dichlorocyclopropane;

(cis- or trans-) 1,2 dichlorocyclopropane; 2

Award point for the correct name corresponding to the related

isomer.

Accept diagrams that do not display 3 dimensional structure.

Award [1 max] for correct structures only, without the

corresponding names.

(b)

2

Cl CH

H

and

CH Cl2

Cl

3 Cl

H

Cl

CH3

Cl

H

and

Cl

HH

H

CH Cl2

[4]


188. (i)

2

OH

CH CH

H

23

C

CH3

OH

CH CH

H

2 3

C

CH3

Award [2] for both tetrahedral structures, or [1] if tetrahedral

structure is not clear.

(ii) plane polarized light;

rotation in opposite/different directions; 2

(iii)

2

C C

H H

CH3 CH3

;

C C

H

HCH3

CH3

;

(iv) curly arrow showing attack by –OH on end H;

curly arrow showing C–Br bond fission;

curly arrow showing formation of double bond;

H2O and Br– shown as products; 3 max

Award [1] each for any three.

If but-2-ene formed, award [2 max].[9]

189. CH3OH + HCOOH → HCOOCH3 + H2O

Award [1] for both reactants and [1] for both products (accept

C2H4O2).

methyl methanoate; 3[3]


190. (a) (CH3)2CO + HCN → (CH3)2C(OH)CN; 1

(b)

H C3

:CN–

C O

δ–

δ+

H C3

C OH C3

CN

CH 3

:

H+

–C OHH C3

CN

CH 3

Suitable diagram with

curly arrow showing attack by :CN– on carbonyl Cδ+;

curly arrow showing pi bond breaking;

curly arrow from :O to H+;

structure of product (CH3)2C(OH)CN; 4

Accept more detailed formula.

(c) (CH3)2C(OH)CN + H+ + 2H2O → (CH3)2C(OH)COOH + NH4+;

carboxylic acid and alcohol; 2

Accept hydroxy(l) instead of alcohol.[7]

191. (a) all C—C bonds in benzene or structure B are 0.139 (nm) (long)/the

same length;

structure A would have C—C bond lengths of 0.154 and 0.134 (nm)/

benzene does not have C—C bond lengths of 0.154 or 0.134 (nm)/

different bond lengths; 2

If no reference to carbon-carbon bonds, award [1].

(b) (i) structure A would have value of (about) –360 (kJ mol–1);

150 (kJ mol–1)/difference between –360 and –210 represents

greater stability of benzene/structure B; 2

(ii) delocalized electrons; 1[5]

192. (a) addition-elimination/condensation; 1


(b)

2

N

H

NO

+ H O;

2N

2

NO2

Award [1] for correct structural formula of the organic product

and [1] for water.

(c) the (crystalline) solid has a characteristic melting point; 1[4]

193. –NO2 is deactivating;

due to its overall electron withdrawing capacity;

which destabilizes the carbocation intermediate;

and causes it to form more slowly; 4[4]


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