Download CHE 312 Answers in BOLD RED EXAM 1 KEY (Ch. 16

CHE312
EXAM1KEY(Ch.16-19)
AnswersinBOLDRED
MultipleChoice(60%;2%each)
PleasemarktheletteroftheBESTanswerforeachquestionclearlyonyouranswersheet.Thankyou!
1.
Ethersolubilityinwaterismostlikethatof__________________ofsimilarmolecularweight.
A.alkanes
B.alcohols
C.alkenes
D.aromatichydrocarbons
2.
WilliamsonEtherSynthesisisbestperformedbyreacting
A.analcoholwithdilutewarmacidB.thealkoxideofaprimaryalcoholwithanyalkylhalide
C.anyalkoxidewithaprimaryalkylhalideD.twoalcoholswithdilutewarmacid
3.
Ethercleavageisareactionoftencarriedoutusingconcentrated
A.H2SO4
B.HBr
C.HF
4.
SharplessEpoxidationisnotablebecauseofitsenantiospecificsynthesisofepoxidesfrom
A.alkenes
B.allylicalcohols
C.cyclicalkenes
D.benzylicalcohols
5.
Ifwereacttheepoxidefrom1-butene+CH3COOOHwithsodiummethoxide(CH3O–Na+)themainproductis:
A.2-methoxy-2-butanol B.2-methoxy-1-butanol C.1-methoxy-2-butanol D.1-methoxy-1-butanol
6.
IfItakethesameepoxideusedinquestion5andtreatitwithacidicmethanolsolution,themainproductis:
A.2-methoxy-2-butanol B.2-methoxy-1-butanol C.1-methoxy-2-butanol D.1-methoxy-1-butanol
7.
Isopropylmethylketoneisthefunctionalclassnameforthesubstitutive(IUPAC)namedsubstance
A.4-methyl-2-pentanone B.3-methyl-2-butanone C.2-methyl-3-butanone D.2-methyl-4-pentanone
8.
Ingenericreactionsofcarbonylgroups,nucleophilesattack_______________whileelectrophilesattack___________
A.alpha-C;carbonylO
B.carbonylO;alphaC
C.carbonylO;carbonylCD.carbonylC;carbonylO
9.
Whichofthesealdehydes&ketonesislikelytobemostreactivetowardnucleophiles?
A.CH3CH2CHO
B.CH3COCH3
C.(CH3)2CHCHO
D.CH3CH2COCH2CH3
D.NaOH
10.
Cyanohydrinsoccurinnatureinallofthefollowingexcept:
A.treebarkandleaves B.seedsofstonefruits
C.cassava(tapioca)
11.
CH3CH2CH2CHOistreatedwithNaBH4inmethanol,thenabitofaqueousacid.Themainorganicproductis
A.1-butanol
B.butanoicacid C.CH3CH2CH2CH(OCH3)2 D.2-pentanol
12.
CH3CH2CH2CHOistreatedwithNH2OH,formingasolidproduct.Thisorganicproductis
A.CH3CH2CH2CH2NH2
B.CH3CH2CH2CH2OH
C.CH3CH2CH2CH=N-OH D.CH3CH2CH2CH=NH
13.
CH3CH2CH2CHOistreatedwithacidicH2Cr2O7.Themainorganicproductis
A.CH3CH2CH2CH2OH
B.CH3CH2CH2COOH
C.CH3CH2CH2CH3
D.CH3CH2CH=CH2
14.
Enaminesformwhensuitablealdehydesorketonesreactwith
A.anyamines
B.primaryamines
C.tertiaryamines
D.secondaryamines
15.
Themainorganicproductofthereactionof3-pentanonewithØ3P=C(CH3)2wouldbe
A.trans-4-octeneB.3-ethyl-2-methyl-2-penteneC.cis-4-octeneD.2-ethyl-3-methyl-3-pentene
16.
Duetothe–OHofcarboxylicacids,theircarbonylCatomhaswhatreactivitycomparedthatofaldehydes&
ketones?
A.itisasreactive
B.itismorereactive
C.itislessreactive
17.
TypicalpKavaluesforcommoncarboxylicacidsareabout
A.15
B.5
C.1
18.
Carbonicacid,H2CO3,isapparentlyaweakeracidthanmightbeexpectedforadicarboxylicacid.Why?
A.itisveryunreactive
B.CO2doesnotreactmuchwithwaterC.itisinsolubleD.itisagas
19.
Whichsequencegivesthebestyieldofbutanoicacidfrom1-butene?
A.HBr+peroxide;thenMg+ether;thendryice;H3O+B.Ozone+Zndust;thenaqueousacidicCrO3
C.HBr;thenMg+ether;thendryice;H3O+D.B2H6;thenH2O2/OH–;thenaqueousacidicCrO3
20.
Whatreagentorsequenceofreagentswillconvertbutanoicacidintobutanal(CH3CH2CH2CHO)
A.H2+Lindlarcatalyst
B.B2H6;thenPCCinCH2Cl2C.LiAlH4;H3O+;PCCinCH2Cl2D.NainNH3(l)
21.
Theusualreagentusedtoconvertcarboxylicacidstoacylchloridesis
A.conc.HCl
B.Cl2inCCl4
C.SOCl2
D.somemillipedes
D.–3
D.PCl3
CHE312Exam1KEY
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22.
Whenmalonicacidisheated,itdecomposeseasilybylossof
A.H2O
B.CH4
C.CO
23.
Amongtheacidderivatives,theoneswiththemoststabilized(leastreactive)carbonylgrouparethe
A.anhydrides
B.amides
C.acylhalides
D.esters
24.
Themostcommonlyavailableandusefulacidderivativesforuseinotherreactionsarethe
A.esters
B.acylhalides
C.amides
D.anhydrides
25.
Innucleophilicacylsubstitution,thereactionsequenceendswhen
A.thecarbonylgroupislost
B.atetrahedralintermediateforms
C.anucleophileattackscarbonylC
D.atetrahedralintermediatedissociates
26.
Thebiggestdisadvantageofacidanhydridesasreagentsforuseinsynthesisisthat
A.halfthecarboxyliswastedB.theyaretooinertC.theyareveryexpensiveD.theyareunstable
27.
WhichoftheacidderivativeswillNOTreactwithaqueousbasetoundergohydrolysis?
A.esters
B.nitriles
C.amides
D.allofthemwillreact
28.
Tomakecyanobenzene(benzonitrile)fromtoluene,thebestsequencetouseis
A.hotKMnO4;NH3,∆;P4O10B.hotKMnO4;NaCNC.NBSinCCl4;Mg+ether;NaCND.NBSinCCl4;NaCN
29.
TreatmentofethylbutanoatewithexcessCH3MgBrgiveswhatmainproductafteraqueousacidworkup?
A.2-pentanone
B.2-methyl-2-pentanol C.2-pentanol
D.3-hexanol
30.
Tomake4-octanonefromCH3CH2CH2CNyoumustreactitwith______________followedbynormalworkup.
A.CH3CH2CH2COCl
B.CH3CH2CH2CH2Br
C.CH3CH2CH2CH2MgBr D.CH3CH2CH2CH2CH2MgBr
D.CO2
Problems(40%;14,12,&14%respectively)
I.
Thereactionshownbelowwillproducetheethanal’sacetalandwaterasthefinalproducts.
DRAWTHESTEPSINTHISMECHANISM.Besuretoincludeallmajorstepsandshowthestructuresofthe
mainintermediatesthatareformedalongtheway.
O
H3C
H+
+2CH3CH2OH
H
H+
O
OH
OH
H
H
H
O
O
H
H
OH2
H
O
Acetalof
ethanal
H
H
O
O
O
H
H
H
O
–H2O
O
O
CHE312Exam1KEY
II.
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FischerEsterificationisprobablythemostimportantlabreactionofcarboxylicacids.Forthealcoholand
theacidshownbelow,givethemechanismofthisreaction.
DRAWTHESTEPSINTHISMECHANISM.Besuretoincludeallmajorstepsandshowthestructuresofthe
mainintermediatesthatareformedalongtheway.
O
H3C
OH
O
H+
+CH3CH2OH
H+
OH
OH
OH
OH
OH
O
O
H
H
ethyl
ethanoate
(ethyl
acetate)
O
H
–H2O
O
theseareminimalsteps;couldalsoincludemorespecifictransfers
ofHionsoffandontoOatomsformorecompleteanswers.
O
O
OH2
OH
O
CHE312Exam1KEY
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III.
Saponification(basecatalyzedaqueoushydrolysisofanester)isaverycommonlyusedreactionofesters.
DRAWTHESTEPSINTHISMECHANISM.Besuretoincludeallmajorstepsandshowthestructuresofthe
mainintermediatesthatareformedalongthewayasthefollowingesterissaponified.
O
H3C
O
Shouldnoteordrawthelaststepasirreversible–akeyaspectofthisreaction!
O
O
O
+
O
O
HO–
–O
OH
OH
NOT
reversible!
O
+
O–
HO