Book3BPart08.docx

Book3BPart08.docx

《Book3BPart08.docx》由会员分享，可在线阅读，更多相关《Book3BPart08.docx（22页珍藏版）》请在冰豆网上搜索。

Book3BPart08

Part8ChemistryofOrganicCompounds（Book3B,p.140–148）

24.（a）

（b）（i）Itcontainsatleastonechiralcarbonatom.Themoleculeischiral.

（ii）Itcontains–CO2Hgroupandisacidic.

（iii）Itisanalcoholthatcontain

grouporacarbonylthatcontains

group.

（c）AisC3H6O3,i.e.2-hydroxypropanoicacid.

（d）

（e）Esterfunctionalgroup.

25.（a）（i）Aqueouschlorine

（ii）

（b）

（c）HCl（aq）

26.（a）Nucleophilicaddition

CN–isgeneratedbythereactionbetweenHCNandabase（e.g.NaOH）.

HCN+OH–H2O+CN–

CN–isthenucleophileanditattackstheelectron-deficientcarbonylcarbonatom.ThetetrahedralintermediateformedthencapturesaprotonfromHCNtoformtheproductandgeneratesanotherCN–forfurtherreaction.

Thus,theoverallreactionis:

（b）Opticalisomerism

（c）（i）AddNa2CO3.

3-Oxobutanoicacid,beinganacid,giveseffervescenceofCO2withNa2CO3whilepropanonedoesnot.2CH3COCH2CO2H+Na2CO32CH3COCH2CO2–Na++H2O+CO2

（ii）Add2,4-dinitrophenylhydrazine.Beingaketone,2-oxobutanoicacidformsanorangeprecipitatewhile3-hydroxybutanoicaciddoesnot.

27.（a）Thereactionofchloroethanewithammoniaproceedsviaanucleophilicsubstitutionmechanismasshownbelow:

Thenucleophilicammoniaattacksthepartiallypositivecarbontowhichtheelectronegativechlorineisattachedresultingintheformationofapentavalenttransitionstate.TheC–ClbondisbeingbrokenastheC–Nbondisformed.Theresultantorganicproductisethylamine,CH3CH2NH2.TheamineisbasicanditreactswiththeacidicHCltogiveethylammoniumchloride.EthylamineisobtainedbyreactingthesaltformedwithabasesuchasNaOH.

（b）Therateofthisreactionincreaseswhenchloroethaneisreplacedbybromoethaneoriodoethane.ThisisbecausethereactioninvolvesthebreakingoftheC–Xbond.E（C–Cl）>E（C–Br）>E（C–I）sincetheoverlapbetweenthecarbonandthehalogenbecomeslesseffectiveasthehalogenincreasesinsizefromCltoI.ItisthuseasiertobreaktheC–BrandC–IbondthanC–Clbond,andtherateofreactionincreaseswhenchloroethaneisreplacedbybromoethaneoriodoethane.

（c）P:

CH3CH2CH2CN

Q:

CH3CH2CH2COOH

R:

CH3CH2CH2COOCH2CH3

（d）（i）Reagents:

ethanolicpotassiumhydroxide/sodiumhydroxide

Condition:

reflux/heat

（ii）

28.（a）

（b）CH3CH2CH2C（CH3）=CHCO2–Na+ThesaltformedisionicwhenstrongelectrostaticforcesbetweenoppositelychargedCH3CH2CH2C（CH3）=CHCO2–andNa+.Thesaltisthusnon-volatileanddoesnotvaporizeeasilyandisodourless.

（c）

29.（a）

（b）2:

nucleophilicsubstitution

3:

hydrolysis

4:

reduction

30.（a）

Suchisomerismisnotpossibleforcyclohexenebecauseina6-memberedring,onlythecis-formispossible:

Asshowninthediagramabove,thetrans-formresultsindistortedringwithgreatanglestrainandisnotformed.

（b）Typeofreaction:

electrophilicaddition

Condition:

roomtemperature

Mechanism:

（1）

（2）

Theelectron-richC=Cpolarizesabrominemoleculeandcausesthebrominemoleculetocleaveheterolyticallyformingthecarbocation1andbromideionintheslowratedeterminingstepasshowninstep

（1）.

Abromideionthenattacksthecarbocation1tofrom3,4-dibromohexaneasshowninstep

（2）.

（c）ThereactionofHBrwithbothtrans-andcis-hex-3-eneresultsintheformationofthesameproduct,3-bromohexane,CH3CH2C*HBrCH2CH2CH3.Sincecarbon-3ischiral,theproductexhibitsopticalisomerism.Inthereaction,H+isfirstaddedtothecarbon-4toformacarbocation.The“+”chargeisoncarbon-3whichhasasp2hybridizationandthemoleculargeometryaboutthiscarbonisthustrigonalplanar.SubsequentattackbyBr–canbefromaboveorbelowtheplaneresultinginbothopticalisomersof3-bromohexanebeingformed.Sincethereisequallikelihoodofcarbon-3beingattackedfrombothaboveandbelow,equimolaramountoftheisomersoftheproductisformed.

（d）CH3CH2COOHandHOOCCH2COOH

31.（a）（i）Opticalisomerism

（ii）

（b）

（c）（i）QcanbedistinguishedfromRusingFehling’ssolution.QreactswithblueFehling’ssolutiontogivethebrick-redprecipitateofCu2Owhereasnobrick-redprecipitateisobservedwithR.

（ii）RcanbedistinguishedfromQusingsodium.EffervesceneofhydrogenisobservedwhensodiumisaddedtoRwhilenohydrogenisevolvedwhensodiumisaddedtoQ.

（d）

32.（a）Duetothehydrophobicbenzenering,eugenolisnotverysolubleinwaterdespitethepresenceofthephenolic–OHgroupwhichenableseugenolmoleculestoformhydrogenbondswithwatermolecules.

Thephenolic–OHgroupisacidicandlosesaprotonwhenreactedwithaqueousNaOHsothatthesodiumsaltofeugenolisformed.Beingionic,theattractionbetweenthissaltandwaterision-dipoleinteractionwhichisstrongerthanhydrogenbonds.HenceeugenolismoresolubleinaqueousNaOHthanwater.

（b）（i）Cold,dilutemanganate（VII）ions

（ii）Hotconcentratedmanganate（VII）ions

（iii）Ethanoylchloride

（iv）Aqueousbromine

（c）（i）Additionpolymerization

（ii）

33.（a）Reagent:

hydrogengas

Condition:

nickelcatalyst,heat

（b）Thetypeofreactionisoxidation.

Reagent:

potassiumdichromate（VI）solutionacidifiedwithdilutesulphuricacid

Condition:

reflux

（c）

‘*’denoteschiralatom

（i）Menthonehastwochiralatoms.

（ii）Mentholhasthreechiralatoms.

（d）（i）Reagentfordehydrationofalcohol:

concentratedsulphuricacid

Condition:

temperatureof170C,excessconcentratedsulphuricacid

（ii）Reagentfornucleophilicsubstitutionofalcohol:

hydrogenchloridegas

Condition:

zincchlorideascatalyst,heat

（e）Thesimpletest-tubereactionistoadd2,4-dinitrophenylhydrazinetomentholandmenthoneseparately.Anorangeprecipitateof2,4-dinitrophenylhydrazoneisobservedforthetesttubecontainingmenthonebutnosuchorangeprecipitateisobservedforthetesttubecontainingmenthol.

34.（a）（i）FeCl3/AlCl3ascatalyst

（ii）Ultra-violetlight

（b）（i）Adoesnotreact.Thisisbecausethechlorineatomisdirectlyattachedtothebenzenering.Duetothedelocalizationofalone-pairofelectronsonthechlorineatomintothebenzenering,theC–Clbondhaspartialdoublebondcharacteranddoesnotcleaveeasily.

（ii）

35.（a）（i）ToproduceAfrommethylbenzene,methylbenzeneisreactedwithchlorineinthepresenceofaluminiumchloride.ToproduceBfrommethylbenzene,methylbenzeneisreactedwithchlorineinthepresenceofultravioletradiation.

（ii）Thecompoundisfirstwarmedwithaqueoussodiumhydroxide.Themixtureiscooledandexcessdilutenitricacidfollowedbyaqueoussilvernitrateisthenadded.AgivesnowhiteprecipitateofsilverchloridebutBgivesawhiteprecipitateofsilverchloride.

（b）（i）

（ii）

（c）ReagentsandconditionsforstepC:

tinandconcentratedhydrochloricacid,reflux

ReagentsandconditionsforstepD:

ethanol,concentratedsulphuricacidascatalyst,reflux

36.（a）LimitedamountofCl2andultra-violetlight

（b）Cl2andFeCl3catalyst

（c）

（d）Reagents:

I2,aqueousNaOH,heat

ObservationwithC:

yellowprecipitate

ObservationwithF:

noyellowprecipitate

（e）MassofCN=0.030gm–360m3

=1.8g

RelativemolecularmassofCN（C6H5COCH2Cl）=154.5

NumberofmolesofCN=

=0.01165mol

（f）（i）H,D,G

（ii）Gisanacidchlorideandundergoeshydrolysisreadilyinwater.

DundergoeshydrolysisonlywhenheatedwithaqueousNaOH.

HdoesnotundergohydrolysisevenwhenheatedwithaqueousNaOH.TheC–Clbondhaspartialdoublebondcharacterandisdifficulttocleave.

37.（a）

（b）For2-methylpropan-2-olasthestartingmaterial,theproductsofreactionsI,IIandIIIareshowninthefollowingtable:

ReactionI

ReactionII

ReactionIII

Product

2-bromo-2-methylpropane

Noreaction

2-methylpropene

38.（a）（i）

（ii）

（b）（i）

（ii）Nucleophilicadditionreaction

（iii）Duetothedifferenceinelectronegativitybetweencarbonandoxygen,thecarbonylcarbonbearsapartialpositivechargeandthecarbonyloxygenbearsapartialnegativecharge.Asthecarbonylcarboncarriesapartialpositivecharge,thecarbonylgroupissusceptibletonucleophilicattack.Whenthenucleophileattacksthecarbonylgroup,itusesitslonepairelectronstoformabondwiththecarbonylcarbonatom.Thecarbonylcarbonatomcanacceptthiselectronpairbecauseonepairofbondingelectronsofthecarbon-oxygenbondcanshiftouttothecarbonyloxygenatom.Thiselectron-richoxygenthentransfersitselectronpairtoanelectropositiveagent.

（iv）EthenecontainsaC=Cdoublebond.Asthereisnodifferenceinelectronegativitybetweentwocarbonatoms,theelectronsinthedoublebondareevenlydistributedovertheC=Cdoublebond.Besides,theC=Cdoublebondisanelectron-richcentre.Therefore,thereisnoelectron-deficientcentrefortheattackofthenucleophileCN-.Thus,ethenewouldnotreactwithHCNinasimilarway.

39.（a）No.Becausethereisnochiralcarboncentreinthemolecule.

（b）Yes.Becausethegroups（oratoms）onthesidesofbothdoublebondsaredifferent.Thusgeometricalisomerismwouldoccur.

（c）（i）

（ii）

（iii）

40.（a）

（b）（i）

ItisbecausethespatialarrangementsoftheatomsorgroupsofatomsaredifferentduetorestrictedrotationabouttheC=Cdoublebond.

（ii）

Theplaneofplanepolarizedmonochromaticlightrotates.

（c）

（d）（i）

（ii）Add3cm3oftheproductformedin（i）toatesttube.Thenadd2cm3of2,4-dinitrophenylhydrazinetothet