HIT4 Additional Worksheet - Solutions

8/6/2019 HIT4 Additional Worksheet - Solutions

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Chemistry HIT4 Additional QuestionsIntegrated Organic Chemistry Revision

Reaction Mechanism & Other Interesting QuestionsSolutions

HCI 2010/P3/3e1 (i) Nucleophilic addition

(ii) I : ethanolic KCN, heat

II : dilute H2SO4, heat OR dilute HCl, heat

III : PBr3, heat OR red phosphorus with Br2, heat

H :

CH3 C

CH2CH3

O

NJC 2010/P3/5a

2 (i) Electrophilic SubstitutionMechanism

Generation of electrophile

CH3CH CH2 H OPO3H2 CH3CHCH3 H2PO4

+ +

5 (ii) Add aqueous NaOH to a separating funnel containing the mixture of phenol andpropanone. Shake thoroughly and drain off the aqueous layer. Acidify the aqueous layer withdilute HCl to recover the phenol.

NJC 2010/P3/4c, d, e3 (a) (i) Only a few Cl radicals are required to initiate/kick-start the propagation reaction,

hence short duration of radiation will be sufficient.

(a) (ii)

CC

CH3

HCH2

H

C C

CH3

H CH2

H

+ CC

CH3

HCH2

H

C C

CH3

H CH2

H

+ ClC C

CH3

H CH2

H

+ Cl ClC C

CH3

H CH2

H

Cl

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When

C C

CH3

H CH2

H

radical reacts with Cl2, 1-chlorobut-2-ene is formed.

(b) 1-chlorobut-2-ene undergoes nucleophilic substitution/hydrolysis with NaOH(aq) to

form AgCl white ppt.2-chlorobut-2-ene does not undergo nucleophilc substitution. The C-Cl bond is harder to breakdue to overlap of Cl p orbital with the adjacent C=C bond. Hence no free Cl ions is formed toreact with Ag+ to form AgCl white ppt.

(c)

HG

Cl

DHS 2010/P3/2b,c4(a) (i) CH3OH + O2 HCHO + H2O

(ii) K2Cr2O7 in dilute H2SO4, heat with distillation

(iii)

CH3OH: HCHO:

sp3 sp2(b) (i) Initiation:

SO2Cl2 Cl + SO2Cl

SO2Cl Cl + SO2

(ii) Propagation:

CH4 + Cl CH3 + HCl

CH3 + SO2Cl2 CH3Cl + SO2Cl

(iii) SO2Cl and CH3[5]

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Structure ElucidationSolutions

MJC 2010/P3/2ciii

5 (1) C2H6.

(2) PV = nRT =r

m

MRT

101000 x 142 x 10-6 =0.25

rMx 8.31 x (127 + 273)

Mr= 57.9 58.0

V is C4H10.

(3) CxHy + (

4

+ )y

x O2 xCO2 +

2

yH2O

Volume of excess O2 + CO2 = 180 cm3

Since NaOH absorbs acidic CO2 gas. Volume of excess O2 =60 cm

3

Volume of CO2 = 180 60 = 120 cm3

Volume of O2 used for combustion = 250 60 =190 cm3

120

20= x

190

20= ( )

4+y

x

x = 6 y = 14

W is C6H14.

C C C C

C

CH

H

H

H

H

H H

H

H

H

H

H

H

H

CH3 C

CH3

H

COOH(4)

S is CH3COOH, T is

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RVHS 0/P

6 (i)formation of the Ag autocatalyst, then

decreases as the reactants are used up.

(ii)

Z is a carbonyl compound /

ddition with 2 molar equivalents

MnO4(aq) to give two identical

te reaction with Na2CO3Y is not a carboxylic

Y undergoes acid-metal reaction with Na Y contains phenol group

201 3/3b

The reaction is autocatalytic as the Ag produced catalyses the reaction. The rateof reaction increases at first due to the

Z undergoes condensation with 2,4-DNPHcontains ketone or aldehyde functional group

1 molar equivalent ofZ undergoes electrophilic a

of Br2Z contains two alkene functional groups

Z undergoes oxidation with hot acidified K

compounds Z contains a plane of symmetry

Y is insoluble in water (due to large hydrophobic benzene ring) but can undergo

acid-base reaction with NaOH(aq) Y contains phenol or carboxylic acid group

Y does not undergo acid-carbonaacid, so Y contains phenol group

OHHO OO

Y Z

HCI7 J K L

2010/P3/4d

C O

CH3

CO2H

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VJC 2007/P3/5cQuestion 8

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ACJC 2006/P3/7a9 D has C:H = 1:1 and no of C> 6, D is basic and

D undergoes electrophilic substitution with aq Br2 to give white pptD is

G undergoes neutralisation with aq NaOH to give DG is

(ii) H is obtained from basic hydrolysis of CH3CH2CNCH3CH2CN + OH

- + H2O CH3CH2COO- + NH3

H is CH3CH2COO-

E reacts with aq alkaline iodine to give yellow ppt,CHI3 and H

E must be a methyl ketone or has the structure C

O

CH3 E is CH3CH2COCH3

(iii) No of mol ofF is 0.693/138.5 = 0.005No of mol of NaOH required = 20.00/1000 x 0.50 = 0.01F is a dibasic acid orF has 2 COOH groups

F is HOOC-CHCl-COOH(iv) B undergoes oxidation and hydrolysis with hot aq KMnO4 to give E (ketone), F (acid)

and G (amine salt)

B must be an amide with C=C functional group

B is

B is refluxed with aq NaOH to give salt CC is

NH2

NH3+

NHCH3CH2 C CCHCl C

CH3 H O

CH3CH2 C CCHOH C

CH3 H O

Na+O-

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HIT4 Additional Worksheet - Solutions