0. common foundation organic q in a level

7/24/2019 0. Common Foundation Organic Q in a Level

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Advo Education Group Pte Ltd

Foundation Organic Chemistry Questions

Alkanes

1.

(a)

What is meant by the term optical isomerism?

(b)

Draw the structural formula of the alkane with the lowest Mr that canexhibit optical isomerism.

2. N98 P1 Q7 (modifed)

Alkanes n many uses in real life application. !wo of these inclue their useas fuels an aerosols.

(a)

Alkanes are commonly use as fuel in the internal combustion ofengine" an branche chain alkanes with # to 1$ carbon atoms permolecule are preferre for this.

(i) Draw the structural formula of the most highly%branchecompoun with molecular formula '1#(

(ii)

Draw the structural formula of a singly%branche chiralcompoun with molecular formula &1)'$$.

(iii)

Write a balance e*uation for the complete combustion ofoctane" '1#. Assuming that air contains $)+ ,$by -olume"what -olume of air at r.t.p./ is neee to burn 1)) g ofoctane?

(iv)

0tate an explain one isa-antage that can arise from theuse of alkanes as fuels. #2

(b)

3n the past" chlorouorocarbons &5&s/ were commonly use asaerosols. 3n light of the en-ironmental concern pose by &5&s" alkanesare now preferentially use as aerosols. 6utane is one such alkane.

(i) When compare to &5&s" why are alkanes preferentially use asaerosols?

(ii)

0tate a isa-antage of using alkanes" such as butane" asaerosols.

$2

3. an!ha-e a molecular formula of &4'76r. exhibits stereoisomerism but

!oes not.6oth an!can be forme from butane by the reaction shown below8

&'9&'$&'$&'9 : !

(a) ;ame the type of reaction unergone an state the conitions forthe abo-e reaction.

$2

(b) Draw the structural formula of an!. $2

(c) Describe the mechanism for the formation of . 92

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(d) 0tate the type of stereoisomerism exhibite by an rawiagrams to illustrate how gi-es rise to its stereoisomerism.

$2

(e)


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C !he central carbon atom of propane is too weakly nucleophilic.

' !he chlorine replaces any of the hyrogen atoms in propane.

. Use o the Data Booklet is relevat to this "estio#

,n the basis of bon energies" what coul be the proucts of the followingreactions?

&'9: &'9&'$&l

N08 P1 Q21

A

&

C

'

A & C '

1" 2an 3 are correct1an 2 only are

correct2an 3 only are

correct1only is correct

*. !he boiling point of pentane an $"$%imethylpropane are 9 o& an 7 o&respecti-ely.

Which of the following suggeste factors make a signicant contribution tothis i@erence in boiling point?

1 !he molecule of $"$%imethylpropane is more compact than that ofpentane.

2 !he co-alent bons in pentane are stronger than those in

$"$imethylpentane.3 !he pentane molecule has more electrons an is therefore more

polarisable.

+. Alkanes can be prepare from iooalkanes by heating uner reux withsoium in ether/ accoring to the e*uation8

$$3 : $;a B $C$ : $;a3




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Which alkanes will be prouce if a mixture containing e*ual amounts of&'9&'$3 iooethane/ an &'9&'3&'9$%ioopropane/ is use?

JJC 08 Prelim P1 Q38

1 &'9&'&'9/&'&'9/&'9

2 &'9&'$&'&'9/&'9

3 &'9&'$&'$&'9

Alkenes

1.

5or each of the following reactions

(i) state the type of reaction"

(ii)

state the conitions" an

(iii)

write balance e*uations (structures o" the ma,or $roduct -ill besucient).

(a)

$"9%imethylbut%1%ene an hyrogen

(b)

hex%$%ene an chlorine gas

(c)

$%ethylbuta%1"9%iene an hyrogen ioie

(d) pent%1%ene an steam

(e)

cyclohexene an potassium manganate33/%state & di'eret reactiocoditios

(")

$%bromobutane an potassium hyroxie to form alkenes/.

2.

$%bromobut%$%ene reacts reaily with bromine issol-e in inert organic sol-entat room temperature.

(a

)

0tate the obser-ations for the reaction.

(b)

Write a balance e*uation for the reaction.

(c)

0tate an escribe the mechanism in-ol-e in the reaction.

(d)

3entify the type of stereoisomerism isplaye by (i) $%bromobut%$%enean (ii)its prouct after bromination. Draw suitable iagrams to illustratethe stereoisomerism.




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3.

6riey escribe a simple laboratory test to istinguish the following pairs ofhyrocarbons. 0tate your obser-ations for the tests an write e*uations for thereactions.

(a)

1%methylcyclohexane an 1%methylcyclohexene

(b)

propene an pent%$%ene

.

is a hyrocarbon with molecular formula &E'14. 3t takes part in the followingreactions8

3t ecolourises a*ueous bromine.

,n aition of hot" aciie potassium manganate33/ solution" butanone

an propanoic aci are forme.

Deuce the structure of an gi-e your reasons.

#CQ

. /0+ 3 Q 23'yrogen bromie reacts with ethene to form bromoethane.

What is the best escription of the organic intermeiate in this reaction?

A 3t contains carbon" hyrogen an bromine.

& 3t has a negati-e charge.

C 3t is an electrophile.

' 3t is a free raical.

/

*. 0 1 Q 20

$%methylbuta%1"9%iene" &'$F&&'9/C&'F&'$is use as a monomer in themanufacture of synthetic rubbers.

Which compoun woul not prouce this monomer on treatment withconcentrate sulfuric aci at 1E)o&?

A &'9/$&,'/&','/&'9

& ',&'$&'&'9/&'$&'$,'




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C ',&'$&'&'9/&','/&'9

' ',&'$&&'9/,'/&'$&'9

/

+. When ethene reacts with '6r in the presence of a*ueous ;a;,9" what are thetwo possible proucts forme?

A C C

H

H

Br Br

H

H

and C C

H

H

Br OH

H

H

C C C

H

H

H Br

H

H

and C C

H

H

Br ONO2

H

H

& C C

H

H

H Br

H

H

and C C

H

H

Br OH

H

H

' C C

H

H

H OH

H

H

and C C

H

H

H ONO2

H

H

/

4. A species of termite prouces a chemical efence secretion which containsthe following molecule.

!o help etermine the structure of this compoun" it is treate with aciiehot concentrate manganate33/ ions.

Which compoun is not prouce in this reaction?

A &,$

& &'9&,&'9

C &'9&,,'




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' ',,&&'$&'$&,&,,'

/

Arenes

1.

;itrobenGene can be forme from benGene.

(a)

0tate the reagents an conitions re*uire for this con-ersion.

(b)

0tate the type of reaction which occurre.

(c)

Describe the mechanism of the reaction using arrows to show mo-ementof electrons/.

2.


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Which of the two routes gi-e a greater yiel of 4%nitrobenGoic aci?

(b)

0uggest how the following con-ersions can be carrie out by gi-ing thereagents an conitions neee for each stage of the con-ersion" an thestructure of the intermeiate.

(i)

benGene C4%bromonitrobenGene

(ii)

methylbenGene '9%bromobenGoic aci

5alogen 'erivatives

1.

A reaction scheme is shown below.

(a)

0tate the reagents an conitions an type of reaction for reactions 3 to 333.

(b)

0tate the reagents an conitions an type of reaction for reactions A to'.

(c)

0uggest the structural formula of compoun 6.

(d)

Describe the mechanism in reactions Can 7.

2.

9CbromoC9Cmethylhexane unergoes the following substitution reactions8




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(a) Describe the mechanism in reactions 3 an 33.

(b) 'ence explain why the resulting mixture obtaine from either reaction is opticinacti-e.

3.

&ompare an explain the i@erence in the reacti-ity of the following groupshalogenate organic compouns towars hyrolysis with a*ueous ;a,'.

(a)

chloroethane an chlorobenGene

(b)

chloroethane" bromoethane an iooethane

.

Describe one test reagents" conitions an obser-ations/ to istinguish thefollowing compouns8

chlorobenGene" chloroethane" iooethane.

.

&ompoun 8 has molecular formula &9'E&l. ,n reuxing 8 with a*ueoussoium hyroxie" it yiels a compoun 9" &9'#," which is oxiise by aciiepotassium ichromate 3/ to #" &9',. &ompoun #gi-es a yellow precipitatewith $"4%initrophenylhyraGine reagent" but fails to gi-e a precipitate withioine in strong alkali.

Deuce the structures of 8" 9an #" gi-ing your reasoning.

5ydro:y Com$ounds

1. Preict the major product of the reactions by balancing the ollo!inge"uation#.3nicate J;o =eactionK if the reaction oes not occur. 0tate the t$pe oreactionunergone in each case.

(a)

(b)




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(c)

(d)

(e)

(")

(g)

(h

)

(i)

(,)

(k)

(l)

(m)

(n)

(o)

($)




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(;)

2.

(a)

Draw the structure of the organic proucts an state the type of reactionsunergone when a compoun with the formula

reacts with

(i) soium"

(ii)

a*ueous soium hyroxie"

(iii)

phosphorus pentachlorie"

(iv)

ethanoic aci"concentrate '$0,4" heat uner reux

(v)

ethanoyl chlorie

(vi)

aciie I$&r$,E" istil

(vii)

a*ueous 6r$

(b)

0tate the obser-ations for the reactions of the abo-e compoun withreagents (iii)" (vi)an (vii).

3. !he ester forme between 9%methylbutan%1%ol an ethanoic aci contributes tothe a-our of ripe pears.

(a)

Draw the structural formula of the ester

(b)

What conitions an reagents woul you use in the laboratory to make theester from the aci an the alcohol name abo-e?

(c

)

Draw the structural formulae of three primary alcohols that are isomers of

9%methylbutan%1%ol" labelling with an asterisk any chiral carbon atom theycontain.

.

6y means of a #imple one%#tep te#t" istinguish the following pairs ofcompouns.

(a)

phenol an phenylmethanol

(b butan%1%ol an $%methylpropan%$%ol




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)

(c)

butan%1%ol an butan%$%ol

Lou shoul inclue in your answer

the reagents an conitions use obser-ations for each compoun

.

A compoun !has molecular formula '1), an exists as a pair of opticalisomers. 3t reacts with phosphorus pentachlorie to gi-e '& lan gi-es a yellowprecipitate when a*ueous alkaline ioine is ae. 0uggest a possible ientityfor!an explain your reasoning.

*.


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(h)

2.

&omplete the following table by rawing the structural formulae of all organic$roductsif any/. 0tate" if any" the observationsof each reaction.

=eagent M&onitions

$"4CD;P'!ollensNreagent"

heat

5ehlingNssolution"

heat

alkaline 3%

$a*/" heat

&'9&',

3. 5or the following con-ersion" gi-e the reagents an conitions for each stepan raw the structures of the intermeiates.

(a)

&'9&'$,' A & &'9&'$&,,'

(b)

&'9&'$,' C ' &'9&','/&,,'

(c)

&'9&,&'9 7 &'9&'6r&'9

. Describe the mechanism of the aition of hyrogen cyanie to butanone.'ence explain why the reaction between butanone an '&; prouces ane*uimolar mixture of two isomers.

. 6y means of a sim$le one%ste$ test" istinguish the following pair ofcompouns8

(a)

pentan%9%one an pentane




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(b)

pentan%$%one an pentan%9%one

(c)

pentan%9%one an pentanal

(d)

pentan%9%one an pentan%9%ol

Lou shoul inclue the reagents" conitions use an obser-ations for eachteste compoun.

*. A certain inustrial cleaner an paint sol-ent was istille to prouce a singlecompoun 'with straight carbon chain.

When 'reacte with $"4CinitrophenylhyraGine" an orange precipitate wasprouce.With alkaline a*ueous ioine" 'ga-e a yellow precipitate.'i not react either with warm aciie potassium ichromate3/ or with

a*ueous bromine.=euction of 'with hyrogen o-er a catalyst prouce an e*uimolar mixture oftwo isomers" 7an F" with the molecular formula &O'1$,.

0uggest the structural formulae for '" 7an Fan explain the reactionsin-ol-e.

Carbo:ylic Acid < its 'erivatives

1.

(a)

=eactions 3" 33 an 333 show three possible methos of preparing &'9&,,'.5or each reaction"

(i) gi-e the reagents an conitions re*uire.

(ii)

state the type of reaction unergone.




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(b)

=eactions 3 to 33 show some common reactions of &'9&,,'.

(i) 0uggest the reagent an conition re*uire for reaction 3.

(ii)

Draw the organic proucts A" &an C.

(iii)

0tate the type of reaction unergone in reactions 3 to 33.

2.

(a)

!he abo-e reaction scheme shows three common reactions for ethanoylchlorie" &'9&,&l. Write balance e*uations for the con-ersion ofethanoyl chlorie to =" >an ?.

(b)

Draw the isplaye structure of @.

(c)

0uggest a possible reagent to con-ert =back to ethanoyl chlorie.

(c)

=ank the following compouns in escening orer of their ease ofhyrolysisi.e. con-ersion of the C&lgroup for the C,' group/ an explain your

reasoning.&'9&,&l &'O&l &'9&'$&l

3. 9%hyroxybutanoic aci has the structure below.

(a)

;ame all functional groups in 9%hyroxybutanoic aci.

(b)

Draw the structure of the organic prouct that is likely to be forme with9%hyroxybutanoic aci when reacts with the following reagents. 0tate thetype of reaction unergone for each reagent use.




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(i) P&lO

(ii) '6r

(iii)

soium

(iv) a*ueous ;a,'(v) aciie I$&r$,Ea*/" heat uner reux

(vi) &'9&'$,'" a few rops of conc. '$0,4" heat uner reux

(vii ethanoyl chlorie

. 'ow may the following con-ersions be carrie out? 0tate clearly the reagentsan conitions re*uire in each step an state the structural formula of anyorganic intermeiate in-ol-e.

(a &'9&'&'9/,' A & &'9&'&'9/&,$'

(b &'9&','/&'9 C ' &'9/$&,'/&,$'

(c &'9&,$' 7 F &'9&'$&,$'

. (a)


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&ompoun &" a iaci that occurs in apples an other fruits" has the followingcomposition by mass8

&" 9O.#+ '" 4.O+ ," O7.E+

&reacts with ethanol in the presence of concentrate sulfuric aci uner reux

to gi-e C" '14,O. &ompoun C e-ol-es hyrogen gas when treate withsoium metal an reacts with aciie potassium ichromate3/ to gi-ecompoun '. &ompoun ' prouces an orange precipitate with $"4%initrophenylhyraGine but has no reaction with 5ehlingNs or !ollensN reagent.

(a &alculate the empirical formula of &.

(b 0uggest structures for compouns&" Can 'an explain the reactions

Organic /itrogen Com$ounds

1.

(a)

=eactions 3 an 33 show two possible methos of preparing ethylamine"&'9&'$;'$.

(i) Hi-e the reagents an conitions for each reaction.

(ii)

0tate the type of reaction unergone for reaction 3 an 33.

(b)

=eactions 333 an 3 show two reactions of ethylamine.

(i) Draw the structural formula of the organic prouct 6.

(ii)

Hi-e the reagent for reaction 3.

(iii)

0tate the type of reaction that occurre in reactions 333 an 3.

2.

2BBQ+(a)%(b) modi&ed

Phenylamine is an important intermeiate compoun for the prouction ofyes.

phenylamine

(a)

Phenylamine can be synthesise from benGene in two steps as shownbelow.




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Draw the structural formula of the intermeiate !an suggest reagentsan conitions for steps 3 an 33.

2. (b)

Phenylamine is a weak base.

(i) Write an e*uation showing phenylamine acting as a base.

(ii)

Arrange the following amines in increasing orer of basic strength anexplain your answer.

(c)

Draw the structure of the prouct forme when phenylamine reacts witha*ueous bromine.

3.

'ow can the following con-ersions be carrie out? 0tate clearly the reagentsan conitions re*uire in each step an ientify" if any" the intermeiateforme.

(a)

&'$F&'$ A &'9&'$;'$

(b &'9&'$&l & &'9&'$&'$;'$

(c)

&'9&,,' C &'9&,;'&'$&'9

Protein#. !here are three pa-alues associate with glutamic aci8 $.1" 4.1 an 7.O.

(a)

>ake use of the pa -alues to suggest the maor species present insolutions of glutamic aci with the following p' -alues.Q p' 1 Q p' 9 Q p' E Q p' 11

(b)

'ence" suggest a -alue for the isoelectric point" p" of glutamic aci.

. Angiotensin 33" a peptie consisting of eight amino acis" is in-ol-e in theregulation of bloo pressure. Partial hyrolysis of Angiotensin 33 gi-es the




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following O fragments as well as the ini-iual amino acis.

argC-alCtyr

ileChisCpro

proCphe

aspCargC-al

-alCtyrCile

Deuce the primary structure of Angiotensin 33.

*.

!he following structure represents a portion of a protein molecule8

(a)

;ame the type of linkage that links the amino acis in this protein.

(b)

What reagent an conitions coul you use to hyrolyse this protein intoits amino acis?

(c)

Draw the structural formula of the three amino acis that woul beprouce by hyrolysing this portion of the protein using the reagentsuggeste in (b).

(d)

Amino acis exist as*witteriosin a*ueous solution.

Draw the structural formula of the Gwitterion forme from amino aci A"an write e*uations to show how it can react as a bu@er.

+. !he formulae of three amino acis are gi-en.

(a)

What is unerstoo by the termprimary str"ct"reof a protein.

(b)

Draw the structure of a section of a protein with the amino aci se*uenceglyCproCala.

(c)

With the ai of a iagram" escribe how a polypeptie chain is hel in theshape of an

Chelix.

(d)

With the ai of a iagram" escribe the Cpleate sheet structure of

protein which constitutes the main material of meat.

4. 2BB1 modi&ed




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!he tertiary structure of a protein is the o-erall threeCimensional shape of apolypeptie. !here are four types of sieCchain = group interactions which holthe tertiary structure in its shape.

(a)

(i) !he cysteine resiues in a protein molecule can form dis"lfde +rid,es.

3llustrate this process by means of a chemical e*uation" gi-en that theformula of the sie%chain of a cysteine resiue is C&'$0'.

(ii) ,ther than isule brige" state the other three types of sieCchain =group interactions" illustrating your answer with suitable pairs ofamino acis gi-en below. -ote8 Draw dia,rams to ill"strate yo"raswer./

(iii)

Which amino aci resiues liste in (a)(ii)are likely to be on the outersurface of a waterCsoluble globular protein?


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0. common foundation organic q in a level

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