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AQA A2 CHEMISTRY

TOPIC 4.10

ORGANIC SYNTHESIS AND ANALYSIS

TOPIC 4.11

STRUCTURE DETERMINATION

BOOKLET OF PAST EXAMINATION QUESTIONS

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1. Consider the following reaction sequence.

C H 3 C H 3

N O 2

C H 3

N H 2

m e t h y l b e n z e n e E F

S t e p 1 S t e p 2

(a) For Step 1, name the mechanism and gie the reagents inoled!

Name of mechanism !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Reagents !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(b) For Step 2, gie a reagent or combination o" reagents! #rite an e$%ation "or this reaction

%sing &H' to represent the red%ctant!

Reagent(s) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Equation !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(c) ie the m/z al%e o" a maor pea* +hich co%ld appear in the mass spectr%m o"

methylbenzene, b%t not in the spectr%m o" either E or F!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(d) ra+ the str%ct%re o" the species "ormed by F in an e-cess o" hydrochloric acid!

(1)

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(e) Compounds G and H are both monosubstituted benzenes and both are isomers of F. Gis a primary amine and H is a secondary amine. Draw the structures of G and H below.

G

H

(2)

(T!"# $ %"&')

2. (a) #rite an e$%ation "or the "ormation o" methyl propanoate, CH3CH2COOCH3, "rom

methanol and propanoic acid!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(1)

(b) Name and o%tline a mechanism "or the reaction bet+een methanol and propanoyl chloride

to "orm methyl propanoate!

Name of mechanism !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mechanism

()

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(c) .ropanoic anhydride co%ld be %sed instead o" propanoyl chloride in the preparation o"

methyl propanoate "rom methanol! ra+ the str%ct%re o" propanoic anhydride!

(1)

(d) (i) ie *+adantage o" the %se o" propanoyl chloride instead o" propanoic acid in

the laboratory preparation o" methyl propanoate "rom methanol!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) ie *+adantage o" the %se o" propanoic anhydride instead o" propanoyl

chloride in the ind%strial man%"act%re o" methyl propanoate "rom methanol!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(e) /n ester contains a benzene ring! 0he mass spectr%m o" this ester sho+s a molec%lar ion

pea* at m/z 13!

(i) ed%ce the molec%lar "orm%la o" this ester!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) ra+ !,possible str%ct%res "or this ester!

(3)

(T!"# 12 %"&')

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3. Compound U is shown below.

C H C H C H C

O

C l3 2 2

(a) Name compo%nd U!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(b) (i) State +hy the mass spectr%m o" U contains t+o molec%lar ion pea*s!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) ie the m/z al%es o" these t+o pea*s!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(c) Name and o%tline a mechanism "or the reaction o" U +ith CH3OH

Name of mechanism !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mechanism

()

(T!"# - %"&')

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4. The proton n.m.r. spectrum of compound Xis shown below.

4

!3

4

!2

4

!1

4

!5

3

!6

3

!7

3

!8

3

!

3

!9

3

!4

3

!3

3

!2

3

!1

3

!5

2

!6

2

!7

2

!8

2

!

2

!9

2

!4

2

!3

2

!2

2

!1

2

!5

1

!6

1

!7

1

!8

1

!

1!

9

1

!4

1

!3

1

!2

C

h

e

m

ic

a

l

sh

i"t,

:p

p

m

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Compo%nd X, C8H12O3, contains both a *etone and an ester "%nctional gro%p! 0he meas%red

integration trace "or the pea*s in the n!m!r! spectr%m o" X gies the ratio sho+n in the table

belo+!

Chemical shi"t, :ppm 4!13 2!8 2!98 2!25 1!2

;ntegration ratio 5!7 5!7 5!7 1!2 1!2

n%mber ratio o" each type o" proton in compo%nd X=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(c) ra+ the part o" the str%ct%re o" X +hich can be ded%ced "rom the presence o" the pea* at

2!25!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(d) 0he pea*s at 4!13 and 1!2 arise "rom the presence o" an al*yl gro%p! ;denti"y the

gro%p and e-plain the splitting pattern!

Alkyl group !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Explanation !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(e) ra+ the part o" the str%ct%re o" X +hich can be ded%ced "rom the splitting o" the pea*s

at 2!8 and 2!98!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(") ed%ce the str%ct%re o" compo%nd X!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(T!"# $ %"&')

. Compo%nd Q has the molec%lar "orm%la C4H8ClO and does not prod%ce misty "%mes +hen

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added to +ater!

(a) 0he in"ra>red spectr%m o" Q contains a maor absorption at 1824 cm?1

! ;denti"y the bond

responsible "or this absorption!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(b) 0he mass spectr%m o" Q contains t+o molec%lar ion pea*s at m:z 15 and m:z 157!

;t also has a maor pea* at m:z 43!

(i) S%ggest +hy there are t+o molec%lar ion pea*s!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) / "ragment ion prod%ced "rom Q has m:z 43 and contains atoms o" !&++

di""erent elements! ;denti"y this "ragment ion and +rite an e$%ation sho+ing its

"ormation "rom the molec%lar ion o" Q!

Fragment ion !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Equation !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(c) 0he proton n!m!r! spectr%m o" Q +as recorded!

(i) S%ggest a s%itable solent "or %se in recording this spectr%m o" Q!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) ie the "orm%la o" the standard re"erence compo%nd %sed in recording proton

n!m!r! spectra!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(d) 0he proton n!m!r! spectr%m o" Q sho+s three pea*s! Complete the table belo+ to sho+

the n%mber o" adacent, non>e$%ialent protons responsible "or the splitting pattern!

.ea* 1 .ea* 2 .ea* 3

;ntegration al%e 3 3 1

Splitting pattern do%blet singlet $%artet

N%mber o" adacent,

non>e$%ialent protons1

(1)

(e) @sing the in"ormation in parts (a), (b) and (d), ded%ce the str%ct%re o" compo%nd Q!

(1)

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(") / str%ct%ral isomer o" Q reacts +ith cold +ater to prod%ce misty "%mes! S%ggest a

str%ct%re "or this isomer!

(1)

(T!"# $ %"&')

/. (a) ra+ the str%ct%re o" ethyl propanoate!

(1)

(b) Name and o%tline a mechanism "or the "ormation o" ethyl propanoate "rom propanoyl

chloride and ethanol!

Name of mechanism!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mechanism

()

(c) 0he mass spectr%m o" ethyl propanoate contains a maor pea* at m/z 98! #rite an

e$%ation sho+ing the "ragmentation o" the molec%lar ion to "orm the species responsible

"or the pea* at m/z 98! Sho+ the str%ct%re o" this species in yo%r ans+er!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

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(d) Draw the structure of another ester which is an isomer of ethyl propanoate and which

gives a major pea at m/z ! "# in its mass spectrum.

(1)

(T!"# $ %"&')

. (a) (i) @sing mass spectrometry, +hat in"ormation in addition toMrcan be obtained "rom

the precise al%e o" the mass o" the molec%lar ion o" an organic compo%nd=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) S%ggest +hy, "or most organic compo%nds, it is possible to detect a pea* at one

mass %nit higher than that o" the molec%lar ion!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(b) Fragmentation o" the molec%lar ion o" methylb%tanone, (CH3)2CHCOCH3, gies rise to

dominant pea*s at m/z 81 and m/z43!

(i) Constr%ct a balanced e$%ation to sho+ ho+ "ragmentation o" the molec%lar ion

gies rise to the pea* at m/z 81!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) ;n the "ragmentation o" (CH3)2CHCOCH3, t+o "ragments +ith m/z 43 are "ormed!

ie the str%ct%ral "orm%la o" each o" these "ragments!

tructure ! tructure "

()

(c) 0+o molec%lar ion pea*s appear in the mass spectr%m o" 2>chloropropane at m/z87

and m/z 75! A-plain +hy t+o molec%lar ion pea*s are "o%nd and +hy the relatie

intensities o" the pea*s are appro-imately 3 to 1, respectiely!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(T!"# 10 %"&')

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-. 0hree sections o" the proton n!m!r! spectr%m o" CH3CHClCOOH are sho+n belo+!

1 2 ! 5 1 1 ! 5 1 5 ! 5 4 ! 4 ! 9 4 ! 4 4 ! 3 1 ! 7 1 ! 8 1 !

: p p m : p p m : p p m

(a) Name the compo%nd CH3CHClCOOH

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(b) A-plain the splitting patterns in the pea*s at 1!82 and 4!44

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(c) .redict the splitting pattern that +o%ld be seen in the proton n!m!r! spectr%m o" the

isomeric compo%nd ClCH2CH2COOH

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

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(d) The amino acid alanine is formed by the reaction of C$%C$ClC&&$ with an e'cess of

ammonia. The mechanism is nucleophilic substitution. &utline this mechanism showing clearly the

structure of alanine.

()

(e) 0he amino acid lysine has the str%ct%re

H

( C H )H N

N H

C C O O H2 2

2

4

ra+ str%ct%res to sho+ the prod%ct "ormed in each case +hen lysine reacts +ith

(i) an e-cess o" a$%eo%s HCl,

(ii) an e-cess o" a$%eo%s NaOH,

(iii) another molec%le o" lysine!

(3)

(T!"# 12 %"&')

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$. (a) (i) #rite an e$%ation "or the red%ction o" pentan>2>one by a$%eo%s NaBH4to "orm

pentan>2>ol!

@se &H' to represent the red%ctant!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) Name and o%tline a mechanism "or this red%ction!

Name of mechanism !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mechanism

(iii) State +hy the pentan>2>ol prod%ced in this reaction is not optically actie!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!()

(b) .redict the m/z al%es o" the t+o most ab%ndant "ragments in the mass spectr%m o"

pentan>2>one!

Fragment ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Fragment " !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(T!"# $ %"&')

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(d) 0he proton n!m!r! spectr%m o" Qsho+s 4 pea*s!

0he table belo+ gies al%es "or each o" these pea*s together +ith their splitting

patterns and integration al%es!

:ppm 2!25 2!6 3!45 3!74

Splitting pattern singlet triplet singlet triplet

;ntegration al%e 3 2 1 2

#hat can be ded%ced abo%t the str%ct%re o" Q"rom the presence o" the "ollo+ing in its

n!m!r! spectr%m=

(i) 0he singlet pea* at 2!25

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) 0he singlet pea* at 3!45

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(iii) 0+o triplet pea*s

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(e) @sing yo%r ans+ers to parts (a), (b) and (d), ded%ce the str%ct%re o" compo%nd Q!

(1)

(T!"# 11 %"&')

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(b) (i) +ive a suitable reagent for ,eaction -.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) .rod%ct Bis "o%nd to be optically inactie! S%ggest +hy this is so!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(iii) ien the table o" in"ra>red absorption data belo+, describe the t+o maor

di""erences bet+een the in"ra>red spectra o" b%tanone and o" B!(4)

(c) O%tline a mechanism "or the "ormation o" b%t>1>ene by the dehydration o" B!

(4)

(d) ra+ the str%ct%re o" the repeating %nit in the polymer +hich can be "ormed "rom

b%t>1>ene!

(1)

(T!"# 1 %"&')

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12. The proton n.m.r. spectrum of an ester A is shown below.

4 3 2 1

Chemical shi"t, :ppm

0he meas%red integration trace gies the ratio 5!95 to 5!95 to 5!89 to 5!89 "or the pea*s at

4!13, 2!32, 1!33 and 1!56, respectiely!

(a) 0he mass spectr%m o" compo%nd Ahas a molec%lar ion pea* at m/z 152!

ed%ce the molec%lar "orm%la o" compo%nd A!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(3)

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(b) #hat is the ratio o" the n%mbers o" each type o" proton=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(c) #hat can be ded%ced abo%t the arrangement o" protons "rom the splitting patterns in the

n!m!r! spectr%m=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(d) ed%ce the str%ct%re o" compo%nd Aand label +ith the letters a, b, c and d the "o%r

gro%ps o" e$%ialent protons!

(1)

(e) /ssign the ario%s signals in the table belo+ to the gro%ps o" protons in compo%nd A

preio%sly labelled a, b, c and d!

Chemical shi"t, :ppm 1!56 1!33 2!32 4!13

Gabel o" gro%p

(4)

(T!"# 10 %"&')

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13. The proton n.m.r. spectrum of an alcohol A C$#-& is shown below

1 ! 7 1 ! 1 ! 4 1 ! 2 1 ! 5 5 ! 7 5 ! 5 ! 4 5 ! 2 5

: p p m

0he meas%red integration trace gies the ratio 5!65 to 5!49 to 2!85 to 1!39 "or the pea*s at

1!92, 1!36, 1!21 and 5!63, respectiely!

(a) #hat compo%nd is responsible "or the signal at 5=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(b) Ho+ many di""erent types o" proton are present in compo%nd A=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(c) #hat is the ratio o" the n%mbers o" each type o" proton=

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!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(d) 0he pea*s at 1!92 and 5!63 arise "rom the presence o" a single al*yl gro%p! ;denti"y

this gro%p and e-plain the splitting pattern!

&roup#!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Explanation##########!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(e) #hat can be ded%ced "rom the single pea* at 1!21 and its integration al%e=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(1)

(") ie the str%ct%re o" compo%nd /!

(1)

(T!"# - %"&')

14. 0he ester "ormed +hen ethanol reacts +ith ethanoic anhydride +as analysed by high>

resol%tion proton n!m!r! spectroscopy!

(i) ie the str%ct%ral "orm%la o" the ester!

(ii) Ho+ many di""erent types o" proton are present in this ester=

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(iii) escribe the splitting pattern o" the ethyl gro%p in the n!m!r! spectr%m o" the ester!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(T!"# 3 %"&')

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15. (a) Define the term structural isomerism.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(2)

(b) 0he graph belo+ sho+s part o" the mass spectr%m o" an organic compo%nd, A, +hich has

the molec%lar "orm%la C4H15!

r e l a t i ea b % n d a n c e

5 1 5 2 5 3 5 4 5 9 5 5 m : e

(i) ra+ graphical "orm%lae "or the str%ct%ral isomers o" C4H15!

;somer 1 ;somer 2

(2)

(ii) S%ggest the "orm%la o" the "ragment that corresponds to each o" the "ollo+ing m:e

al%es sho+n in the mass spectr%m o" compo%nd A!

43 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

26 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

19 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(3)

(iii) ed%ce +hich o" the isomers dra+n in (i) corresponds to compo%nd A! ie a

reason "or yo%r ans+er!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (2)

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(c) (i) uggest graphical formulae for two structural isomers with the molecular

formula C%$/&-. 0ach isomer contains a single functional group. The functional groups are

different in the two isomers.

I%+& 3 I%+& 4

(2)

(ii) ie the name o" the type o" compo%nd that each isomer represents!

;somer 3 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

;somer 4 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!(2)

(T!"# 13 %"&')

1/. Aach o" the parts (a) to (") belo+ concerns a di""erent pair o" isomers! ed%ce one possible

str%ct%ral "orm%la "or each o" the species Ato L!

(a) Aand Bhae the molec%lar "orm%la C2H4O2! /n a$%eo%s sol%tion o" Areacts +ith

calci%m carbonate to liberate carbon dio-ide, b%t Bdoes not!

A B

(2)

(b) Cand Dhae the molec%lar "orm%la C3H7O! Chas a broad absorption band at

3355 cm?1

in its in"ra>red spectr%m, b%t Ddoes not!

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C D

(2)

(c) Eand Fhae the molec%lar "orm%la C3HC12! Ehas only one pea* in its lo+ resol%tion

proton n!m!r! spectr%m b%t Fhas t+o!

E F

(2)

(d) Gand Hhae the molec%lar "orm%la C3HO and both hae strong absorption bands at

abo%t 1855 cm?1

in their in"ra>red spectra! Gt%rns acidi"ied potassi%m dichromate(;)

sol%tion green b%t Hdoes not!

G H

(2)

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(e) Iand Jhave the molecular formula C1$23r. Ishows optical activity but Jdoes not.

I

(2)

(") Kand Lhae the molec%lar "orm%la C9H15! Khas a +ea* absorption band at

195 cm?1

in its in"ra>red spectr%m, b%t L does not!

K L

(2)

(T!"# 12 %"&')

1. (a) Name and o%tline a mechanism "or the reaction bet+een propanone and hydrogen

cyanide!

Name !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Mechanism

()

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(b) Carbonyl compo%nds can be red%ced to alcohols!

(i) #rite an e$%ation "or the red%ction o" propanone to the corresponding alcohol and

identi"y a s%itable red%cing agent! ;n the e$%ation yo% may %se the symbol &H' "or

the red%cing agent!

Equation !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Re'ucing agent!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

(ii) 0+o isomeric carbonyl compo%nds, Aand B, +ith molec%lar "orm%la C4H7O both

hae 3 pea*s in their lo+>resol%tion proton n!m!r! spectra!

resol%tion proton

n!m!r! spectr%m +hereas red%ction o" B"orms alcohol D+hich has 4 pea*s in its

lo+>resol%tion proton n!m!r! spectr%m!

ra+ one possible str%ct%re "or each o" these 4 compo%nds!

aronyl compoun'A AlcoholC

aronyl compoun'B Alcohol D

(/)

(T!"# 11 %"&')

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18. Compound A C$#4& reacts with 5a3$1 to give B C$#-&. Treatment of Bwith

concentrated sulphuric acid yields compound C C$#4. 6cid7catalysed hydration of Cgives a

mi'ture of isomers Band D.

Fragmentation o" the molec%lar ion o" A, &C9H15O'I

, leads to a mass spectr%m +ith a maor

pea* at m/z98! 0he in"ra>red spectr%m o" compo%nd Ahas a strong band at 1819 cm?1

and the

in"ra>red spectr%m o" compo%nd Bhas a broad absorption at 3395 cm?1

(0able)! 0he proton

n!m!r! spectr%m o" Ahas t+o signals at 1!5 (triplet) and 2!42 ($%artet), respectiely

(Spectr%m)!

@se the analytical and chemical in"ormation proided to ded%ce str%ct%res "or compo%nds A, B,

Cand D, respectiely! ;ncl%de in yo%r ans+er an e$%ation "or the "ragmentation o" the

molec%lar ion o" Aand acco%nt "or the appearance o" the proton n!m!r! spectr%m o" A! A-plain

+hy isomers Band Dare "ormed "rom compo%nd C!

S+!&%

4 2 5 : p p m

C o m p o % n d , C H OA 9 1 5

(T!"# 20 %"&')

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19. (a) The infra7red spectrum of compound A C%$/&- is shown below.

1 5 5

9 5

5

4 5 5 5 3 5 5 5 2 5 5 5 1 5 5 51 9 5 5 9 5 5

X Y

0

ra

n

sm

itta

n

c

e

:

C

# a e n % m b e r : c m

? 1

;denti"y the "%nctional gro%ps +hich ca%se the absorptions labelled XandY!

@sing this in"ormation dra+ the str%ct%res o" the three possible str%ct%ral isomers "or A!

Gabel as A the str%ct%re +hich represents a pair o" optical isomers!(/)

(b) ra+ the str%ct%res o" the three 5&"*+67"8*al*enes +ith molec%lar "orm%la C9H15

ra+ the str%ct%res o" the three dibromoal*anes, C9H15Br2, "ormed +hen these three

al*enes react +ith bromine!

One o" these dibromoal*anes has only three pea*s in its proton n!m!r! spectr%m! ed%ce

the integration ratio and the splitting patterns o" these three pea*s!(10)

(T!"# 1/ %"&')

20. (a) 0he reaction o" b%t>1>ene +ith chlorine prod%ces 1,2>dichlorob%tane, C4H7Cl2

(i) ien that chlorine e-ists as a mi-t%re o" t+o isotopes,39

Cl and38

Cl, predict the

n%mber o" molec%lar ion pea*s and their m/z al%es in the mass spectr%m o"C4H7Cl2

(ii) 0he mass spectr%m o" 1,2>dichlorob%tane contains pea*s at m/z 88 and 86! ra+

the str%ct%re o" the "ragment ion +hich prod%ces the pea* at m/z 88 and +rite an

e$%ation sho+ing its "ormation "rom the molec%lar ion!(/)

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(b) The reaction of but7-7ene with hydrogen chloride forms a racemic mi'ture of the

stereoisomers of -7chlorobutane.

(i) Name the type o" stereoisomerism sho+n by 2>chlorob%tane and gie the meaning

o" the term racemic mixture! State ho+ separate samples o" the stereoisomers co%ld

be disting%ished!

(ii) By considering the shape o" the reactie intermediate inoled in the mechanism o"

this reaction, e-plain ho+ a racemic mi-t%re o" the t+o stereoisomers o" 2>

chlorob%tane is "ormed!()

(c) 0he reaction o" b%t>2>ene +ith chlorine prod%ces 2,3>dichlorob%tane, C4H7Cl2

(i) State the n%mber o" pea*s, their integration ratio and any splitting o" pea*s in the

proton n!m!r! spectr%m o" 2,3>dichlorob%tane!

(ii) Compo%nd S, an isomer o" C4H7Cl2, prod%ces a proton n!m!r! spectr%m +hich

consists only o" a singlet, a triplet and a $%artet +ith an integration ratio o" 3J3J2respectiely!

Compo%nd T, also an isomer o" C4H7Cl2, prod%ces a proton n!m!r! spectr%m +hich

consists only o" t+o singlets +ith an integration ratio o" 3J1

ra+ the str%ct%res o" S and o" T!(/)

(T!"# 1$ %"&')

21. B%tenedioic acid, HOOCCHCHCOOH, occ%rs as t+o stereoisomers! One o" the isomers

readily "orms the acid anhydride C4H2O3+hen +armed!

(a) ra+ the str%ct%res o" the t+o isomers o" b%tenedioic acid and name the type o"

isomerism sho+n!

@se the str%ct%res o" the t+o isomeric acids to s%ggest +hy only one o" them readily

"orms an acid anhydride +hen +armed! ra+ the str%ct%re o" the acid anhydride "ormed!(/)

(b) ;denti"y one electrophile +hich +ill react +ith b%tenedioic acid and o%tline a mechanism

"or this reaction!(4)

(c) #rite an e$%ation "or a reaction +hich occ%rs +hen b%tenedioic acid is treated +ith ane-cess o" a$%eo%s sodi%m hydro-ide!

(2)

(d) escribe and e-plain the appearance o" the proton n!m!r! spectr%m o" b%tenedioic acid!(3)

(T!"# 1 %"&')

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22. *ropanoyl chloride can be used together with a catalyst in tep # of the synthesis of #7

phenylpropene from benzene via compounds Pand Qas shown below.

C O C H C H C H ( O H ) C H C H C H C H C H22 3 3 3

S t e p 1 S t e p 2 S t e p 3

P Q

(a) 0he mechanism o" Step 1 is an electrophilic s%bstit%tion! #rite an e$%ation to sho+ the

"ormation o" the electrophile "rom propanoyl chloride! O%tline the mechanism o" the

reaction o" this electrophile +ith benzene in Step 1!()

(b) 0he mass spectr%m o" Pcontains a molec%lar ion pea* at m/z 134 and maor

"ragmentation pea*s at m/z 159 and 88! ;denti"y the species responsible "or the pea* at

m/z 159 and also that responsible "or the pea* at m/z 88! #rite an e$%ation "or the

"ormation, "rom the molec%lar ion, o" the species responsible "or the pea* at m:z 159!(4)

(c) NaBH4can be %sed in the reaction in Step 2! Name the mechanism inoled in this

reaction! Eolec%les o" Q sho+ optical isomerism b%t the sample o"Q"ormed in Step 2 is

optically inactie! State, in terms o" their str%ct%re, +hy molec%les o" Qsho+ optical

isomerism! A-plain, by re"erence to the mechanism, +hy the sample o" Qobtained in

Step 2 is not optically actie!()

(d) ;denti"y a s%itable reagent "or the reaction in Step 3!

Name the type o" stereoisomerism sho+n by the prod%ct o" this reaction! State +hat is

re$%ired in the str%ct%re o" molec%les to allo+ them to sho+ this type o" stereoisomerism!(4)

(T!"# 20 %"&')

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23. (a) 0ster X C$%C$-C&&C$% can be produced by the reaction between

propanoyl chloride and methanol. 5ame Xand outline a mechanism for this reaction. 5ame the

mechanism involved.(/)

(b) 0he proton n!m!r! spectr%m o" Xis sho+n belo+ together +ith that o" an isomeric

ester,Y! ed%ce +hich o" Spectr%m 1 and Spectr%m 2 is that obtained "romX! @se T"5#+

1 on the ata Sheetand the integration data on the spectra to help yo% to e-plain yo%r

ded%ction! S%ggest a str%ct%re "or Y!

1 5

1 5

6

6

7

7

8

8

9

9

4

4

3

3

2

2

1

1

5

5

: p p m

: p p m

S p e c t r % m 1( i n c l % d i n g i n t e g r a t i o n d a t a )

S p e c t r % m 2( i n c l % d i n g i n t e g r a t i o n d a t a )

2

2

3

3

3

3

(4)

(T!"# 10 %"&')

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24. The three compounds C$%C$-C$-C$-&$ (C$%)%C&$ and C$%C$-C$-C$& can be

disting%ished by %se o" the "ollo+ing three reagents

1! potassi%m dichromate(;) acidi"ied +ith dil%te s%lph%ric acid

2! 0ollensD reagent

3! ethanoic acid, together +ith a small amo%nt o" concentrated s%lph%ric acid!

(a) ;denti"y +hich o" these three organic compo%nds +o%ld red%ce acidi"ied potassi%m

dichromate(;)! ie the str%ct%res o" the organic prod%cts "ormed! #rite a hal">e$%ation

"or the red%ction o" dichromate(;) ions in acidic sol%tion!(/)

(b) ;denti"y +hich one o" these three organic compo%nds +o%ld red%ce 0ollensD reagent! ie

the str%ct%re o" the organic prod%ct "ormed! #rite a hal">e$%ation "or the red%ction o"

0ollensD reagent!(3)

(c) ;denti"y +hich o" these three organic compo%nds +o%ld react +ith ethanoic acid in the

presence o" concentrated s%lph%ric acid! ;n each case, gie the str%ct%re o" the organicprod%ct "ormed!

(4)

(d) State the n%mber o" pea*s in the proton n!m!r! spectra o" CH3CH2CH2CH2OH and o"

(CH3)3COH! (/nalysis o" pea* splitting is not re$%ired!)

(2)

(T!"# 1 %"&')

2. (a) ra+ the str%ct%re o" each o" the three *etones +hich hae the molec%lar "orm%la

C9H15O! For each compo%nd gie the ratio o" the areas %nder each pea* in its lo+>

resol%tion proton n!m!r! spectr%m!(/)

(b) ra+ the str%ct%re o" each o" the "o%r aldehydes +hich also hae the molec%lar "orm%la

C9H15O! Gabel +ith the letter Xthe compo%nd +hich has only t+o pea*s in its lo+>

resol%tion proton n!m!r! spectr%m! Gabel +ith the letterYthe compo%nd +hich has "ie

pea*s +ith the ratios o" the areas %nder each pea* 3J3J2J1J1 in its lo+>resol%tion proton

n!m!r! spectr%m! Gabel +ith the letter 9 the compo%nd +hich sho+s optical isomerism!()

(c) #hen carbonyl compo%nds react +ith HCN, racemic mi-t%res are o"ten prod%ced! Namethe type o" mechanism inoled and e-plain +hat is meant by the term racemic mixture!

Choose any carbonyl compo%nd +hich does *! "orm a racemic mi-t%re +hen it reacts

+ith HCN and dra+ the str%ct%re o" the prod%ct "ormed by the reaction o" this carbonyl

compo%nd +ith HCN!(4)

(d) A-plain +hy aldehydes react +ith 0ollenDs (or FehlingDs) reagent b%t *etones do not!(3)

(T!"# 20 %"&')

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26. (a) Describe by giving reagents and stating observations how you could

distinguish between the compounds in the following pairs using a simple test7tube reaction for eachpair.

(i)

C H C H

H H

C CH C H CO H C H Oa n d3 3

3 3

A B

(ii) C D

Ca n dH C

H C

C H

C HC

3 3

3 3

(iii)

C H C O O C H C H C H C O O Ha n d3 33 2

E F

(-)

(b) State ho+ compo%nds E and F in part (a)(iii) aboe co%ld be disting%ished by their in"ra>

red spectra, +itho%t %sing the "ingerprint region! A-plain ho+fingerprinting is %sed to

identi"y a compo%nd!(3)

(c) S%ggest the str%ct%re o" the "ragment responsible "or the maor pea* in the mass spectr%m

o" compo%nd E and state its m/z al%e! #rite an e$%ation sho+ing the "ormation o" this

"ragment "rom the molec%lar ion!(4)

(T!"# 1 %"&')

2. @se the data gien on the bac* o" the .eriodic 0able (.0) to help yo% ans+er this $%estion!

Compo%nds A to G are all isomers +ith the molec%lar "orm%la CH12O2

(a) ;somer A, CH12O2, is a ne%tral compo%nd and is "ormed by the reaction bet+een

compo%nds X and Y in the presence o" a small amo%nt o" concentrated s%lph%ric acid!

X and Y can both be "ormed "rom propanal by di""erent redo- reactions!

X has an absorption in its in"ra>red spectr%m at 1895 cm?1

!

ed%ce the str%ct%ral "orm%lae o" A, X and Y! ie s%itable reagents, in each case, "or

the "ormation o" X and Y "rom propanal and state the role o" concentrated s%lph%ric acid

in the "ormation o" A!()

(b) ;somers B, C, D and E all react +ith a$%eo%s sodi%m carbonate to prod%ce carbon

dio-ide!

ed%ce the str%ct%ral "orm%lae o" the three isomers that contain an asymmetric carbon

atom!

0he "o%rth isomer has only three singlet pea*s in its proton n!m!r! spectr%m! ed%ce the

str%ct%ral "orm%la o" this isomer and label it E!(4)

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(c) 8somer F C/$#-&- has the structural formula shown below on which some of the

protons have been labelled.

3 2 2 2 3C H C H O C H C H C C H

Oa )

/ proton n!m!r! spectr%m is obtained "or F! @sing 0able 1 at the bac* o" the .eriodic0able (.0), predict a al%e o" "or the protons labelled a and also "or those labelled !

State and acco%nt "or the splitting patterns o" the pea*s assigned to the protons a and !(/)

(d) ;somer G, CH12O2, contains si- carbon atoms in a ring! ;t has an absorption in its in"ra>

red spectr%m at 3285 cm?1

and sho+s only three di""erent proton enironments in its

proton n!m!r! spectr%m! ed%ce a str%ct%ral "orm%la "or G!(2)

(T!"# 1$ %"&')

2-. 0he conersion o" compo%nd A into compo%nd B can be achieed in t+o steps as sho+n belo+!

C H C H

H B r

A B

C CXC H C HC H B r C H3 32 3

3 3S t e p 1 S t e p 2

0he intermediate compo%nd, X: has an absorption at 195 cm?1

in its in"ra>red spectr%m!

(a) ;denti"y compo%nd X! A-plain yo%r ans+er!(2)

(b) For each step in this conersion, gie the reagents and essential conditions re$%ired and

o%tline a mechanism!(11)

(c) Sho+ ho+ the n%mber o" pea*s in their proton n!m!r! spectra +o%ld enable yo% to

disting%ish bet+een compo%nds A and B!(2)

(T!"# 1 %"&')

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29. 8n the presence of 6lCl% ethanoyl chloride reacts with the dialylbenzene A C9$#4 to

form a sing!compound B C#4$#-&. Compound Bis converted into C C#4$#1& on treatment with

5a3$1. Compound Dis produced when compound Cis warmed with concentrated $-&1.

Compo%nd Bhas a strong absorption band in the in"ra>red at 179 cm?1

, compo%nd Chas a

broad absorption at 3345 cm?1

and compo%nd Dhas an absorption band close to 135 cm?1

!

(a) Sho+ ho+ the in"ormation proided in the $%estion and the data in the 0able belo+ can

be %sed to ded%ce str%ct%res "or compo%nds A, B, Cand D!

A-plain the signi"icance o" the "act that B is obtained as a single compo%nd!($)

(b) Name the types o" reaction ta*ing place in each step and o%tline a mechanism "or the

"ormation o" compo%nd D"rom compo%nd Cand concentrated s%lph%ric acid!()

(c) A-plain brie"ly +hy compo%nd Ccan e-ist in stereoisomeric "orms!(2)

(T!"# 1- %"&')

30. .roton n!m!r! spectroscopy can be %sed to disting%ish bet+een the "ollo+ing isomersJ

HOCH2CH2OCH3 HOCH2OCH2CH3 CH3OCH2OCH3 A B C

For each o" these isomers, describe the appearance o" the high>resol%tion proton n!m!r! spectr%m

and acco%nt "or any splitting patterns! /ss%me that the OH protons are not co%pled to any other

protons!

(T!"# 1 %"&')

31. (a) 0he nitration o" benzene is an e-ample o" electrophilic s%bstit%tion! 0he reagents "or this

nitration are concentrated s%lph%ric acid and concentrated nitric acid in a 1J1 ratio and the

reaction is per"ormed at 5 C!

(i) A-plain +hat is meant by the term electrophile and the termsustitution#(2)

(ii) ie the name, or "orm%la, o" the electrophile inoled in this reaction and +rite an

e$%ation or e$%ations to sho+ its "ormation "rom the reagents! #rite a mechanism"or the nitration o" benzene!

(/)

(iii) A-plain +hy the temperat%re o" the reaction sho%ld not be allo+ed to rise aboe

5C!(1)

(b) Chlorobenzene is also prepared by electrophilic s%bstit%tion! State the reagent(s) and

condition(s) re$%ired "or this reaction to occ%r!(3)

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(c) The structural formulae of compounds A" B" C and D" which are the four structural

isomers of molecular formula C1$2Cl are given below.

CH3CH2CH2CH2Cl CH3CH(Cl)CH2CH3 (CH3)2CHCH2Cl (CH3)2C(Cl)CH3

A B C D

Go+ resol%tion1H NE< analysis o" compo%nds A: B: Cand Dprod%ces t+o spectra

+ith 4 pea*s, one spectr%m +ith 3 pea*s and one spectr%m +ith a single pea*!

(i) ie the name o" compo%nd D.(1)

(ii) ;denti"y the compo%nd (A: B: C or D) +hose NE< spectr%m sho+s a single pea*!

A-plain yo%r reasoning!(2)

(iii) ;denti"y the compo%nd (A: B: C or D) +hose NE< spectr%m sho+s three pea*s

and ded%ce the ratio o" the areas %nder these pea*s! A-plain yo%r reasoning! (3)

(i) #hen re"l%-ed +ith an alcoholic sol%tion o" KOH, compo%nd B %ndergoes an

elimination reaction! 0+o str%ct%rally isomeric prod%cts are "ormed! ra+ the

graphical "orm%lae o" these t+o str%ct%ral isomers!(2)

() ra+ the graphical "orm%la "or the prod%ct o" the reaction bet+een compo%nd C

and NaOH(a$)! ie an o%tline o" the mechanism inoled in this reaction!(4)

(T!"# 24 %"&')

32. (a) 0he "ragmentation o" a molec%lar ion (E?

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33. 6 molecular ion pea at mlz!9/ is present in the mass spectrum of each of three

organic compounds A" B and C. 0ach compound has only two peas in its low7resolution protonn.m.r. spectrum.

A is a hydrocarbon!

B and C are isomers and both hae a strong absorption near 1855 cm

?1

in their in"ra>red spectra!

/ table o" in"ra>red absorption data is proided belo+!

(a) For each compo%nd, gie the molec%lar "orm%la and dra+ a possible str%ct%re! ed%ce

the ratio o" the pea* areas in the lo+>resol%tion proton n!m!r! spectr%m o" each

compo%nd!($)

(b) escribe ho+ yo% co%ld disting%ish bet+een B and C %sing a chemical test! Ho+ co%ld B

or Cbe identi"ied %sing its in"ra>red spectr%m=()

(c) D and E are isomers o" B and C.

D has in"ra>red absorptions at 3355 cm?1

and also at 195 cm?1

!

E has an in"ra>red absorption at 3355 cm?1

b%t none near 195 cm?1

!

ra+ and label one possible str%ct%re each "or D and E. A-plain yo%r ans+er!(4)

(T!"# 1- %"&')

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34. (a) 0'plain what is meant by the fingerprint region of an infra7red spectrum and

describe how it is used to confirm the identity of organic molecules.(4)

(b) Aach o" three isomeric esters, Q: Rand S, o" molec%lar "orm%la C9H15O2has a branched

str%ct%re!

Qhas only t+o pea*s in its lo+ resol%tion proton n!m!r! spectr%m, b%t Rand Seach hae

three pea*s!

Hydrolysis o" Rin acid conditions "orms compo%nds Tand U! 0he lo+>resol%tion proton

n!m!r! spectr%m o" Thas three pea*s and that o" Uhas t+o pea*s! ;n"ra>red spectra o" T

and Uare sho+n belo+!

ra+ str%ct%res o" the compo%nds Q: R:S, Tand Uand e-plain ho+ the n!m!r! and i!r!

data s%pport yo%r concl%sions! / table o" in"ra>red absorption data is proided belo+!

1 5 5

6 57 5

8 5

5

9 5

4 5

3 5

2 5

1 5

5

0

ra

n

sm

itta

n

c

e

:

4 5 5 5 3 5 5 3 2 5 5 2 7 5 5 2 4 5 5 2 5 5 5 1 7 5 5 1 5 5 1 4 5 5 1 2 5 5 1 5 5 5 7 5 5 9 5

# a e n % m b e r : c m ? 1

T

1 5 5

6 5

7 5

8 5

59 5

4 5

3 5

2 5

1 5

5

0

ra

n

sm

ittan

c

e

:

4 5 5 5 3 5 5 3 2 5 5 2 7 5 5 2 4 5 5 2 5 5 5 1 7 5 5 1 5 5 1 4 5 5 1 2 5 5 1 5 5 5 7 5 5 9 5

# a e n % m b e r : c m ? 1

U (11)(T!"# 1 %"&')

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3. Simple organic compo%nds, incl%ding str%ct%ral isomers, can be disting%ished "rom each other

by chemical tests, or by spectroscopic methods, or by a combination o" both! 0his $%estion

concerns the "o%r compo%nds +hose str%ct%ral "orm%lae are sho+n belo+!

CH3(CH2)2CHO (CH3)2CHCHO CH3COC2H9 CH3COOC2H9

A B C D

(a) ra+ graphical "orm%lae "or A, B, C and D, clearly indicating +hich is +hich! ie the

names o" A, B, Cand D!(-)

(b) Compo%nd Dcan be made by a reaction called esteri"ication! State the names o" !,

compo%nds needed "or the reaction and gie a condition %sed in the reaction!(3)

(c) ie the name and dra+ the graphical "orm%la o" an isomer o" compo%nd Dthat is *!an

ester!(2)

(d) escribe *+chemical test that +o%ld disting%ish bet+een Band C, and state +hat yo%

+o%ld obsere in each case!(3)

(e) 0he1H NE< spectra o" A, B, Cand Dcan be %sed to disting%ish bet+een some o" the

str%ct%res by considering the n%mbers o" pea*s and the ratios o" the areas %nder them!

0he "ollo+ing table sho+s some res%lts o" a1H NE< inestigation into A, B, Cand D!

Aach o" the "o%r spectra is re"erred to by a n%mber!

S+!&% N%5+& ; +"' R"!8 ; "&+" *6+& !+ +"'

1 3 J 1 J 1

2 4 3 J 2 J 2 J 1

3 3 3 J 2 J 3

4 3 3 J 2 J 3

(i) #hich compo%nd (A, B, Cor D) corresponds to spectr%m 1= ie a reason "oryo%r choice!

(2)

(ii) #hich compo%nd (A, B, Cor D) corresponds to spectr%m 2= ie a reason "or

yo%r choice!(2)

(iii) A-plain +hy spectr%m 3 and spectr%m 4 hae the same n%mber o" pea*s and the

same ratio o" areas %nder them!(1)