Acceptable Answers Reject Mark. Acceptable Answers Reject Mark. ALLOW Iron/Fe or Zn/Zinc for tin Conc for concentrated. Acceptable Answers Reject Mark

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Zoe Rodgers
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1 (a)(i) (a)(ii) Concentrated nitric acid AND concentrated sulfuric acid concentrated nitric and sulfuric acids Concentrated HNO and concentrated H SO 4 Extra reagents To prevent multiple substitutions/ to stop di- or trinitrobenzene forming To stop further substitution (of NO )/ further nitration Further addition of nitro groups further reaction (a)(iii) Tin/ Sn AND concentrated HCl/ concentrated hydrochloric acid Dilute HCl Iron/Fe or Zn/Zinc for tin Conc for concentrated (b)(i) C 6 H 5 NH + Cl C 6 H 5 NH Cl (b)(ii) Skeletal formula C 6 H 5 for benzene Undisplayed CH Structural formula

2 (b)(iii) i i (transition metal) complex ion Transition metal complex / copper complex Formulae of ions () F (azo) dye / azo compound / diazo compound diazonium compound molecule for compound () b(iv) Benzenediazonium chloride Phenyldiazonium chloride Benzadiazonium chloride Diazonium salt b(v) HCl + NaNO Hydrochloric acid + Sodium nitrite / nitrate(iii) alternative cation to Na + HNO Concentration of HCl HCl + HNO

3 b(vi) any substitution positions C 6 H (CH ) NH C 6 H (CH ) NH H- 6H (CH ) NH Kekule structure Total for = 0 marks (a)(i) Overall yield higher Reduces use of solvents ( chemicals / reactants) Less loss of chemicals Less waste products References to Energy / fuel / CO References to atom economy More efficient conversion Fewer side products (a)(ii) Lowers (operating) temperature / energy (requirements) Less fuel needed References to catalyst properties such as lowers E a, can be re-used Atom economy (b)(i) CH COCl + AlCl CH CO + + AlCl 4 Structural formulae not required Positive charge may be anywhere on the electrophile. Curly arrows even if incorrect

4 (b)(ii) TE on incorrect electrophile in (b)(i) If benzene used instead of substituted benzene If final product is not,4 only MP and can be scored Curly arrow from on or within the circle to positively charged carbon Curly arrow from anywhere within the hexagon Arrow to any part of the electrophile including to the + charge (which can be anywhere on the electrophile) () Intermediate structure including charge with horseshoe covering at least carbon atoms, and facing the tetrahedral carbon and with some part of the positive charge within the horseshoe dotted horseshoe () Curly arrow from C H bond to anywhere in the benzene ring reforming delocalized structure of a stable molecule () Curly arrow on or outside the hexagon Partial bonds to H and CH unless part of a D with a wedge bond Correct Kekulé structures score full marks Ignore any involvement of AlCl 4 in the final step

5 (b)(iii) No HCl formed (as a by-product) Ethanoic acid easier to recover Chlorine Reverse arguments Chlorine containing product References to ozone layer, acid rain, global warming Atom economy (c)(i) Catalyst (more) easily recovered / separated can be filtered Facilitates the use of flow (rather than batch) systems references to properties of catalysts

6 Reaction (c)(ii) (red) phosphorus / P / P 4 and iodine / I PI / HI () Reaction Hydrochloric acid / HCl(aq) or sulfuric acid / H SO 4 (aq) () NaI + H SO 4 PI 5 Just H + / H O + and reflux / heat Award second mark for Acid / H + / H O + and reflux NaOH(aq) / KOH(aq) () () reflux / heat without acid or with warm or <50 C (reflux) then acidify with HCl(aq) or H SO 4 (aq) Omission of states throughout () (c)(iii) C=O / carbonyl group (only) in carboxylic acid / ibuprofen Absorption / peak at (cm ) If no other mark has been awarded, then (for mark) OH in both but in alcohol (cm ) but in carboxylic acids 00 to 500 (cm ) () () ketone (cm ) Single values rather than ranges

7 (d)(i) (A chiral molecule is) non-superimposable on its mirror image. (d)(ii) Asymmetric (tetrahedral) carbon atom / has a carbon atom bonded to four different groups / atoms Has two enantiomers Functional (as in functional groups) Reference to rotation of plane polarized light Acceptable Answers molecules / species (for groups) Reject Mark any clear indication of chiral carbon (d)(iii) (A racemic mixture is) an equimolar mixture of the two enantiomers / (optical) isomers Just no effect on plane polarised light (for equimolar mixture) equal amounts / concentrations / volumes / proportions 50:50 mixture

8 (d)(iv) Any two of. All the ibuprofen is useful (rather than half). No need for separation of isomers / enantiomers. No need for a more complex synthesis forming just one enantiomer 4. Sometimes one enantiomer has negative effects 5. Smaller dosage may be used (For point 4 above) Dose / inactive isomer is less likely to be harmful Reference to cost / yield / atom economy / side effects (a)(i) HNO + H SO 4 H O + + HSO NO HNO + H SO 4 H O + HSO 4 + NO + -step version of these involving H NO + Correct electrophile () correct equation(s) ()

9 (a)(ii) NO + as electrophile TE on incorrect electrophile in (a)(i) Curly arrow from on or within the circle to positively charged nitrogen Curly arrow from anywhere within the hexagon Arrow to any part of the electrophile including to the + charge () Intermediate structure including charge with horseshoe covering at least carbon atoms, and facing the tetrahedral carbon and with some part of the positive charge within the horseshoe Curly arrow from C H bond to anywhere in the benzene ring reforming delocalized structure () () Correct Kekulé structures score full marks Ignore any involvement of anion in the final step

10 (a)(iii) Benzene ring in phenol has higher electron density O / OH donates electron density to the (benzene) ring () Because lone pair of electrons on (phenol) oxygen is donated to / overlaps with / interacts with (π electrons of benzene) ring () (a)(iv) Substitution may also occur at the / 6 ring positions / ortho position other / / 5 / meta ring positions / isomers further substitution occurs By-products formed (a)(v) Tin /Sn & (conc.) hydrochloric acid / HCl(aq) LiAlH 4 / NaBH 4 Iron/ Fe for tin HCl for HCl(aq) (a)(vi) Yield = (00 x 0.5 x 0.74 x 0.85) = 5.75 / 5.7 / 5.7 / 6 (%) 6.0 and other rounding errors

11 (b)(i) Insoluble impurities are removed by the hot filtration () Soluble impurities are removed by the cold filtration () (b)(ii) 5ºC and 95ºC () Because the lowest proportion ( amount ) of paracetamol remains in solution (at the end) () Just greatest difference in temperature (b)(iii) Measure melting temperature TLC (with UV light) Boiling temperature HPLC Ignore Must melt over range of ºC Data = data book value c(i) Peak at m/e = 5 clearly labelled M Alternative labels c(ii) 4 = CH CO + / C H O + C H 7 + uncharged species CONH + Ignore position of charges

12 (d) Limit number of tablets sold Give (oral) advice at the point of sale Use packs with tablets individually wrapped Only sell on prescription / doctor s advice Label packet Reduce the (tablet) dose

IGNORE Just benzene has a delocalised ring Benzene does not have C=C double bonds Any references to shape/ bond angles. Acceptable Answers Reject Mark

1(a) All carbon to carbon bonds same length/ longer C-C and shorter C=C not present 1 IGNORE Just benzene has a delocalised ring Benzene does not have C=C double bonds Any references to shape/ bond angles