Alcohols. Nomenclature. 57 minutes. 57 marks. Page 1 of 9

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Julianna Fields
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1 ..0 Alcohols Nomenclature 57 minutes 57 marks Page of 9

2 M. (a) % O =.6 % () If % O not calculated only M available C O () = 5. =.5 =.5 Ratio: : 0: ( C 0 O) () If arithmetic error in any result lose M If percentage composition calculation done zero (b) (i) Type of alcohol: Tertiary () Reason: No hydrogen atom on central carbon () Penalise missing bonds / incorrect bonds once per paper (c) (i) Aldehyde () Ignore named aldehydes or their structures, penalise wrong named compound O + [O] O + O () Balanced () C 0 O is OK as a reactant [O] can be over arrow C 7 O not accepted for product, but C 5 O is OK If use C or C 5 compounds no marks in C.E of wrong alcohol (iii) Name Butanoic acid () Structure: COO () mark conseq. or as stated 5 (d) Advantage: Fast reaction OR pure product OR continuous process OR cheap on manpower OR high yield, 00% alcohol () Disadvantage: igh technology OR ethene from non renewable source OR expensive equipment not just costly () Not answers based on fermentation Page of 9

3 (e) [8] M. (a) (i) Potassium (OR sodium) dichromate(vi) OR correct formula OR potassium manganate(vii) (Oxidation state not needed, but must be correct if included) (Penalise errors in the formula or oxidation state, but mark conditions) Acidified OR SO / Cl (NOT with KMnO ) / PO / NO (Ignore heat or reflux) (Credit acidified as part of reagent) Oxidation or redox NaB OR LiAl OR /Ni CO + [] (O) (Credit in the equation if has been chosen as reagent) (b) (i) (Structure must show aldehyde structure) (Credit C 5 as alternative to ) Page of 9

4 M Tollens reagent OR ammoniacal silver nitrate OR AgNO + N OR Fehling s solution OR acidified potassium dichromate M stays colourless stays blue stays orange (Provided reagent is correct, credit no reaction, no change, nothing, no observation for M) M silver mirror / deposit OR black / grey precipitate red / brown / orange precipitate / solid goes green (Credit other correct reagents and observation) (For M, penalise AgNO alone, penalise Ag(N ), penalise potassium dichromate, etc., but, in each case, mark on and credit correct M and M) (If totally wrong reagent or no reagent, CE = no marks for M,M or M) [9] M. (a) Compounds with the same molecular formula but different structures due to different positions of the same functional group on the same carbon skeleton/chain (b) Compound A is butan--ol only Compound C is butanone or butan--one (penalise but--ol, but allow repeat error for but--one) (credit butane--ol) Page of 9

5 (c) (i) oxidation or redox (iii) (iv) (v) K Cr O 7 or potassium dichromate(vi) (penalise the dichromate ion or incorrect oxidation state, but mark on) acidified or SO (or other identified strong acid) (penalise + ) (do not credit the acid unless M has been correctly attempted) (heat under) reflux OR use excess oxidising agent correctly drawn structure of -methylpropan--ol (insist on clearly drawn C-C and C-0 bonds) correctly drawn structure of methanoic acid (insist on C-0 and C=O displayed in the formula) (d) (i) Tollens reagent or this whole reagent specified (ammoniacal silver nitrate) OR Fehling s solution OR acidified potassium dichromate(vi) correctly drawn structure of methylpropanal (insist on C- and C=O of aldehyde displayed in the formula) [] Page 5 of 9

6 M. (a) (i) M pentan--one only M CO (insist on C=O being drawn out) (penalise use of C 7 ) aldehyde ( ) O ketone ( ) CO (insist on a clear structure for the C=O of the functional groups, but do not be too harsh on the vertical bonds between carbon atom son this occasion) (If both structures correct, but wrong way around, award one mark) (ignore names) (b) (i) O + [O] COO (accept C 9 O going to C 9 COO) (insist on a balanced equation for example do not credit [O] over the arrow alone) pentanoic acid (credit pentan oic acid) (c) (i) O OR pentan ol (If both a structure and a formula are given, credit either correct one of these provided the other is a good, if imperfect, attempt) Primary (credit o or ) [8] M5. (a) Pentan--one ONLY but ignore absence of hyphens (b) Functional group (isomerism) Both words needed Page 6 of 9

7 (c) (i) Award credit provided it is obvious that the candidate is drawing the Z / cis isomer The group needs to be O but do not penalise poor C C bonds or absence of brackets around O Trigonal planar structure not essential Restricted rotation (about the C=C) OR No (free) rotation (about the C=C) (d) M Tollens (reagent) (Credit ammoniacal silver nitrate OR a description of making Tollens ) (Do not credit Ag +, AgNO or [Ag M Fehling s (solution) / Benedict s (Penalise Cu + (aq) or CuSO but mark M and M) (N ) + ] or the silver mirror test on their own, but mark M and M) M silver mirror OR black solid or black precipitate M (stays) colourless OR no (observed) change / no reaction M Red solid/precipitate (Credit orange or brown solid) M (stays) blue OR no (observed) change / no reaction If M is blank CE = 0, for the clip Check the partial reagents listed and if M has a totally incorrect reagent, CE = 0 for the clip Allow the following alternatives M (acidified) potassium dichromate(vi) (solution); mark on from incomplete formulae or incorrect oxidation state M (turns) green M (stays) orange / no (observed) change / no reaction OR M (acidified) potassium manganate(vii) (solution); mark on from incomplete formulae or incorrect oxidation state M (turns) colourless M (stays) purple / no (observed) change / no reaction In all cases for M Ignore nothing (happens) Ignore no observation Page 7 of 9

8 (e) (i) Spectrum is for Isomer or named or correctly identified The explanation marks in (e) depend on correctly identifying Isomer. The identification should be unambiguous but candidates should not be penalised for an imperfect or incomplete name. They may say the alcohol or the alkene or the E isomer If Isomer is correctly identified, award any two from (Strong / broad) absorption / peak in the range 0 to 550 cm or specified value in this range or marked correctly on spectrum and (characteristic absorption / peak for) O group /alcohol group No absorption / peak in range 680 to 750 cm or absence marked correctly on spectrum and (No absorption / peak for a) C=O group / carbonyl group / carbon-oxygen double bond Absorption / peak in the range 60 to 680 cm or specified value in this range or marked correctly on spectrum and (characteristic absorption / peak for) C=C group / alkene / carbon-carbon double bond If 6(e)(i) is incorrect or blank, CE=0 Allow the words dip OR spike OR trough OR low transmittance as alternatives for absorption. Ignore reference to other absorptions e.g. C-, C-O [0] Page 8 of 9

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M1. (a) Functional group (isomerism) 1

M1. (a) Functional group (isomerism) 1 M. (a) Functional group (isomerism) (b) M Tollens (reagent) (Credit ammoniacal silver nitrate a description of making Tollens ) (Ignore either AgNO or [Ag(NH ) 2 + ] or the silver mirror test on their