Acceptable sequence of stages are: chlorination. nitration, reduction, chlorination nitration. nitration, chlorination, reduction, reduction

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1 Question er Mark Guidance 1 (a) (i) Response requires three stages Acceptable sequence of stages are: chlorination nitration, reduction, chlorination nitration nitration, chlorination, reduction, reduction chlorination, nitration, reduction Reduction must be a later stage than nitration Mark according to which sequence chosen. Stage 1 organic product: Cl OR O 2 chemicals: Cl 2 AD AlCl 3 OR HO 3 AD H 2 SO 4 Stage 2 organic product: Cl O 2 OR H 2 For organic products, ALLOW C 6 H 5 O 2 OR C 6 H 5 Cl OR C 6 H 5 H 2 ALLOW O 2 AD H 2 DO OT ALLOW ClC 6 H 4 O 2 (formula ambiguous) DO OT ALLOW molecular formulae IGORE any additional structures shown eg 2- (ortho) and 3- (meta) substituted isomers In chemicals boxes, IGORE temperatures IGORE catalyst For chlorination chemicals, ALLOW Cl 2 AD FeCl 3 OR Cl 2 AD Fe OR Cl 2 AD halogen carrier For nitration chemicals, concentrated not required for HO 3 OR H 2 SO 4 BUT... DO OT ALLOW dilute chemicals: HO 3 AD H 2 SO 4 OR Sn AD HCl Stage 3 chemicals: Cl 2 AD AlCl 3 OR Sn AD HCl 5 For reduction chemicals, concentrated HCl not required but DO OT ALLOW dilute For Sn/HCl ALLOW addition of a also IF it is clear that it is a second step BUT. DO OT ALLOW Sn AD HCl AD a IGORE catalyst

2 Question er Mark Guidance (a) (i diazonium ion ALLOW sign up to halfway along triple bond from left-hand Cl group MUST be displayed IGORE presence of Cl DO OT ALLOW Cl substituent on benzene ring DO OT ALLOW: Cl 2 azo dye Cl = group MUST be displayed 2 In azo dye, ALLOW as alternative to phenol group: O OR O a OR Oa ALLOW phenol part substituted at any carbon (ie 2,3 or 4 position for ) i.e. HO IGORE geometry/shape, i.e. ALLOW = Mark independently DO OT ALLOW if Cl is missing from benzene ring in EITHER structure

3 Question er Mark Guidance (b) O δ mark 2 S δ O O O O S H mark 1 step 1 mark 4 O intermediate = mark 3 4 AOTATIOS MUST BE USED mark 1 curly arrow from π-delocalised ring in benzene to S δ in SO 3 ALLOW curly arrow from the ring OR from within the ring mark 2 curly arrow from one S=O double bond to the O (to produce a S O ) ALLOW curly arrow to any O in SO 3 mark 3 intermediate showing delocalisation over 5 carbons Intermediate must have correct SO 3 structure FULLY displayed DO OT ALLOW intermediate with broken ring less than halfway up in correct orientation: mark 4 curly arrow from C H bond reforming π- delocalised ring in benzene Stand alone mark IGORE responses after STEP 2

4 Question er Mark Guidance ALLOW Kekulé mechanism O δ mark 2 S δ O O O O S H mark 1 mark 4 step 1 O intermediate = mark 3 ALLOW double bonds shown in other Kekulé arrangement (c) (i) Various possibilities, eg: O Br ALLOW 1, 2, 3 or 4 Br atoms substituted on phenol ring at carbon atoms 2, 3, 5 or 6 BUT must be in correct position shown DO OT ALLOW O or Oa H 3 C C ALLOW for side chain: CH 3 C but aromatic part of structure must be shown H Br IGORE any additional inorganic products in boxes (even if incorrect Reaction with a O ALLOW Oa OR O as alternative to O a DO OT ALLOW O a OR O a (i.e. a without charge) H 3 C C O - a Oa must be in correct position shown H 2 ALLOW for side chain: CH 3 C but aromatic part of structure must be shown IGORE any additional inorganic products in boxes (even if incorrect)

5 Question er Mark Guidance (c) (ii) Hydrolysis with a(aq) On BOTH structures, ALLOW Oa OR O as alternative to O a O DO OT ALLOW O a OR O a (i.e. a without charge) H 3 C C O - a Oa must be in correct position shown on 2nd structure ALLOW CH 3 COOa/ CH 3 CO 2 a OR CH 3 COO / CH 3 CO 2 H 2 O - a ALLOW one mark for carboxylic acid AD phenol, rather than sodium salts: Mark independently 2 O H 3 C C H 2 ALLOW H 2, CH 3 Total 15 IGORE any additional inorganic products in boxes (even if incorrect)

6 Question Expected Answers Marks Additional Guidance 2 a Bond length intermediate between/different from (short) C=C and (long) C C H hydrogenation less exothermic than expected (when compared to H hydrogenation for cyclohexene) Only reacts with Br 2 at high temp or in presence of a halogen carrier / resistant to electrophilic attack Please annotate, use ticks to show where marks are awarded b i compound A O 2 if O 2 in wrong position penalise here and ECF for rest of b(i) and b(ii) 3 ALLOW all carbon carbon bonds the same length ALLOW H hydrogenation less (negative) than expected ALLOW H hydrogenation different from that expected DO OT ALLOW H halogenation/hydration ALLOW doesn t decolourise/react with/polarise Br 2 ALLOW doesn t undergo addition reactions (with Br 2 ) ALLOW any 4-nitro-1,3-dimethylbenzene drawn in any orientation ALLOW O 2 H 3 C CH 3 drawn in any orientation compound B H 2 4 ALLOW any 4-amino-1,3-dimethylbenzene drawn in any orientation ECF amine of incorrect compound A (e.g. position of O 2 or lack of methyl sticks/groups) compound C ALLOW diazonium chloride salt of 1,3-dimethylbenzene ECF diazonium salt/compound of incorrect compound B IGORE Cl ion allow not allow 2

7 Question Expected Answers Marks Additional Guidance ALLOW if charge is floating between the two s only if it is closer to the correct allow not allow compound D HO ALLOW any of O - ALLOW O in place of

8 Question Expected Answers Marks Additional Guidance ii Equation to show formation of O 2 ion mark 1 HO 3 2H 2 SO 4 H 3 O 2HSO 4 O 2 ALLOW HO 3 H 2 SO 4 H 2 O HSO 4 O 2 HO 3 H 2 SO 4 HSO 4 H 2 O 3 H 2 O O 2 If O 2 is in correct position do not penalise even if compound A in b(i) is not in correct position O 2 mark 4 curly arrow from C H bond back to reform ring AD correct products H O 2 O 2 H 5 ALLOW mark 2 curly arrow must be from 1,3- dimethylbenzene to O 2 and ECF for marks 3 and 4 DO OT ALLOW intermediate -ring must be more than 1 / 2 way up H O 2 mark 2 curly arrow from ring to O 2 mark 5 - H HSO 4 mark 3 intermediate with ring broken in the correct place H 2 SO 4 Link to compound A in part (i) cannot score full marks [in b(i) & b(ii)] if O 2 is not adjacent to a methyl ALLOW CH 3 s shown ALLOW H 3 O HSO 4 H 2 O H 2 SO 4 iii 2 1 o other correct response Total 13

9 Question Expected Answers Marks Additional Guidance 3 (a) ALLOW C 6 H 6 Br 2 C 6 H 5 Br HBr Br 2 Br HBr (b) (i) White precipitate OR white solid OR white crystals 1 DO OT ALLOW multiple substitution DO OT ALLOW Br DO OT ALLOW colourless DO OT ALLOW white ppt and bubbles Br Br 2 DO OT ALLOW Br 3 C 6 H 2 OR 2,4,6-tribromophenol OR tribromophenol (ii) 1,2-Dibromocyclohexane Br (iii) MUST spell delocalised/delocalized or localised/localized correctly once in the answer to obtain all 5 marks benzene electrons or π-bonds are delocalised phenol a lone or non-bonded pair of electrons on the oxygen or the group is (partially) delocalised into the ring cyclohexene electrons are localised OR delocalised between two carbons benzene has a lower electron density OR phenol has a higher electron density OR cyclohexene has a higher electron density benzene cannot polarise or induce a dipole in Br 2 OR phenol can polarise the Br 2 OR cyclohexene can polarise Br 2 or the Br Br bond 1 5 ALLOW 1,2dibromocyclohexane OR 1-2dibromocyclohexane OR 12dibromocyclohexane OR cyclo-1,2-dibromohexane DO OT ALLOW dibromocyclohexane OR C 6 H 10 Br 2 OR structures ALLOW diagram to show overlap of all 6 p-orbitals for delocalisation DO OT ALLOW benzene has delocalised structure or ring ALLOW diagram to show movement of lone pair into ring for phenol ALLOW diagram or description of overlap of 2 adjacent p-orbitals for bonding in cyclohexene DO OT ALLOW cyclohexene has a C=C double bond IGORE slip if cyclohexene is written as cyclohexane but - bonding correctly described DO OT ALLOW charge density OR electronegativity instead of electron density ALLOW Br OR electrophile Br as alternate to polarise

10 (c) ALLOW H H 2 H 3 C H H3C H 3 C 5 IGORE Cl - ion DO OT ALLOW if ring is connected to the triple bond in the diazonium or if diazonium has a negative charge ALLOW one mark for correct displayed diazonium if alkyl group is not shown ALLOW ALLOW H 3 C H 3 C 2 ALLOW ECF on incorrect amine for both marks for one mark ALLOW ALLOW H 3 C H 3 C HO 2 HCl and temp < 10 o C OR ao 2 HCl and temp < 10 o C alkaline AD phenol (if temperature stated must be below 10 o C) Total 14 for one mark for one mark ALLOW a OR K & C 6 H 5 OR phenoxide ion OR C 6 H 5 O ALLOW reagents and conditions from the equations