Organic chem

© SAJC Chemistry Unit 2009 1

2012 JC 2 H2 Chemistry Revision

Topic 10: Organic Chemistry

MCQ – Section A ACJC/PRELIM 2009/P1/Q23 1 The drug cortisone has the formula shown.

O

O

CH3

CH3

CO

OH

CH2OH

How many chiral centres are present in the molecule after its reaction with LiAlH4?

A 5 B 7 C 9 D 11


ACJC/PRELIM 2009/P1/Q24 2 Ethene reacts with aqueous bromine to give CH2BrCH2Br and CH2BrCH2OH.

Which statement is correct for the above reaction?

A Both products can be hydrolysed to form the same diol.

B Both products are non-polar.

C Both products are obtained via nucleophilic addition.

D The dibromo product exhibits optical isomerism.

ACJC/PRELIM 2009/P1/Q25 3 CS, whose structure is shown below, is an active component of „tear gas‟ and

is readily hydrolysed.

CH C

CN

CN

Which of the following is a possible hydrolysis product of CS?

A

CH2

C

CNNC

H

B

CH C

NH2

NH2

C

CH C

CO2H

CO2H

D

CN


ACJC/PRELIM 2009/P1/Q26 4 The following compound undergoes the given reaction sequence.

CH2CH2OH

OH

MnO4 / H+_

heat

SOCl2ED

Which of the following could be product E?

A COCl

OH

B COCl

Cl

C CH2COCl

OH

D CH2COCl

Cl

ACJC/PRELIM 2009/P1/Q27 5 In which sequence is it correctly stated that the value of pKa decreases

continuously?

A CH3CO2H > CCl3CO2H > C2H5OH > C6H5OH

B CCl3CO2H > CH3CO2H > C2H5OH > C6H5OH

C C2H5OH > C6H5OH > CH3CO2H > CCl3CO2H

D C6H5OH > C2H5OH > CH3CO2H > CCl3CO2H


ACJC/PRELIM 2009/P1/Q28 6 Phenol reacts with diazonium chloride as shown.

OH

0 - 5 oC

N NCl -

OH

N

N

+ HCl

Which term describes this type of reaction?

A electrophilic addition

B electrophilic substitution

C free-radical substitution

D nucleophilic addition


ACJC/PRELIM 2009/P1/Q29 7 In the study of the polypeptide structure of A, it was digested using two

different enzymes. The fragments obtained were separated using electrophoresis. Analysis of the fragments from each digestion gave the following results:

Digestion using the first enzyme: Digestion using the second enzyme:

gly-pro-val val-asp-gly-thr

ser-pro-gly pro-gly

asp-gly phe-leu-ser

thr-phe-leu gly-pro

What is the correct sequence of polypeptide structure of A?

A pro-gly-pro-val-asp-gly- thr-phe-leu-ser-pro-gly

B gly-pro-val- ser-pro-gly- asp-gly- thr-phe-leu

C gly-pro-val-asp-gly- thr-phe-leu-ser-pro-gly

D ser-pro-gly-pro-val-asp-gly- thr-phe-leu-ser

ACJC/PRELIM 2009/P1/Q30 8 Which of the following reagents may be used to distinguish between

methanoic acid and benzaldehyde?

A Tollen‟s reagent

B 2,4-dinitrophenylhydrazine

C Lithium aluminium hydride

D Hydrogen chloride

AJC/PRELIM 2009/P1/Q20 20 The diagram shows the structure of chlolecalciferol, which is a form of vitamin

D.

HO

How many chiral carbon atoms are present in this molecule?

A 4 B 5 C 6 D 7


AJC/PRELIM 2009/P1/Q21 21 Which of the following gives the largest number of isomers on reacting with hot

ethanolic potassium hydroxide?

A (CH3)3CCH2Cl

B CH3CH2CHClCH3

C (CH3)2CHCH(CH3)CH2Cl

D CH3CH2CH(CH3)CH(CH3)Cl

AJC/PRELIM 2009/P1/Q22 22 In the molecule shown below, which carbon atom is most likely to be attacked

by a nucleophile?

O2N C C C

H

H

H

CH3

Cl

A B

CD AJC/PRELIM 2009/P1/Q23 23 Straight chain alkanes undergo cracking at high temperatures and in the

presence of catalyst.

Which of the following does not represent a correct cracking reaction?

A C10H22 C3H8 + C5H10 + C2H4

B C13H28 C4H8 + C6H14 + CH3CH=CH2

C C7H16 CH3CH=CH2 + CH(CH3)3

D C11H24 C4H10 + CH2=CH2 + C5H10


AJC/PRELIM 2009/P1/Q24 24 The following compound is produced when ethene reacts with bromine in the

presence of concentrated aqueous sodium nitrate.

C CH

H

ONO2

H

Br

H

Which of the following descriptions about the organic intermediate in this reaction is correct?

A It has a negative charge.

B It is a free radical.

C It contains carbon, hydrogen and bromine atoms.

D It contains carbon, hydrogen, oxygen and nitrogen atoms.

AJC/PRELIM 2009/P1/Q25 25 Boranes, such as BH3, are readily added across a carbon-carbon double bond

and the resulting product can be oxidised with alkaline H2O2.

H2O2

OH-C C

CH3

H

H

CH3

+ H B

H

HC

CH3

CH3 CH2

H BH2

C

CH3

CH3 CH2

H OH

+ HO BH2

Which compound is produced when 3-methylpent-2-ene is treated with BH3, followed by alkaline H2O2?

A CH3CH2CH(CH3)CH(CH3)OH

B CH3CH2CH(OH)CH(CH3)2

C CH3CH2CH2CH(CH3)2OH

D (CH3CH2)2C(CH3)OH


AJC/PRELIM 2009/P1/Q26 26 Which of the following salts would produce the most alkaline solution when

dissolved in water?

A C6H5O-Na+

B C2H5O

-Na+

C C2H5CO2

-Na+

D C2H5NH3

+Cl-

AJC/PRELIM 2009/P1/Q27 27 Which procedure gives the best yield of phenylbenzoate, C6H5CO2C6H5?

A Reacting C6H5CO2H with SOCl2, then adding C6H5OH.

B Reacting C6H5OH with NaOH, then adding C6H5COCl.

C Refluxing a mixture C6H5CO2H and C6H5OH with concentrated H2SO4.

D Reacting C6H5OH with SOCl2, then adding C6H5CO2H.

AJC/PRELIM 2009/P1/Q28 28 When an organic compound L was treated with phosphorous pentachloride,

fumes of hydrogen chloride were evolved. When L was warmed with Fehling‟s solution, a brick-red precipitate was obtained. Which of the following is likely to be compound L?

A CH2COCH3HO

B CH2CHOHO

C CH(OH)CH2CHO

D CO2CH2CH2OH


AJC/PRELIM 2009/P1/Q29 29 Silk fibroin is a type of fibrous protein made up almost entirely of –pleated

sheets. The main amino acids found in silk fibroin are alanine, glycine, serine and cysteine. The structures of these amino acids are given below. H2N CH COOH

H

H2N CH COOH

CH3

H2N CH COOH

CH2OH

H2N CH COOH

CH2SH

glycine alanine serine cysteine

Which of the following statements about the type of interactions present in silk fibroin is not correct?

A The –pleated sheets are held together by hydrogen bonding.

B There are van der Waals‟ forces between glycine and alanine in the protein.

C There are disulphide linkages present in silk fibroin.

D Serine forms ionic bonds with another serine amino acid in the protein.

AJC/PRELIM 2009/P1/Q30 30 How many different tripeptides can be produced from the partial hydrolysis of

the following octapeptide (eight amino acid residues)?

Gly – Leu – Asp – Asp – Leu – Gly – Leu – Asp

A 3 B 4 C 5 D 6

IJC/PRELIM 2009/P1/Q14 14 When the molecule below is heated with hydrogen gas in the presence of nickel

catalyst, how many chiral centres does the product molecule possess?

CH3

CH3

CH(CH3)2

O

COOH

CH2OH

A 5 C 6

B 7 D 8


IJC/PRELIM 2009/P1/Q15

15 Which of the following reagents could not be used to distinguish between compound X and Y?

A I2 in NaOH (aq) C Cu2+ in alkaline solution

B PCl5 D acidified potassium dichromate

IJC/PRELIM 2009/P1/Q16 16 Compound Q has the following properties.

(i) It produces white fumes when PCl5 is added. (ii) It does not react with Na2CO3 but forms a soluble salt in aqueous NaOH. (iii) It gives an orange precipitate with 2,4–dinitrophenylhydrazine.

Which one of the following could be Q?

A

COCH3

OH

C

COOH

CH2COCH3

B OH

CH2CH2CHO

CH2OH

D COOCH3

CH2CH2OH



17 Wedelolactone, the naturally occurring active ingredient of herbal medicine and has been extensively used in South American native medicine as snake anti-venom.

Which of the following is true about Wedelolactone?

A It can react with 5 moles of aqueous bromine.

B It gives an orange precipitate with 2,4-dinitrophenylhydrazine.

C It is resistant to hydrolysis in both acidic and alkaline medium.

D It results in the formation of green Cr3+ ions from an acidified solution of Cr2O7

2- ions. IJC/PRELIM 2009/P1/Q18

18 Which reaction scheme proposed will most likely lead to a successful reaction giving the products given?

A

B


C

D


19 Concentrated ammonia was heated in a sealed tube with excess bromoethane, C2H5Br. Which of the following products will not be formed?

A C4H11N

B C5H13N

C C6H15N

D C8H20NBr


20 0.01 mol of compound R is refluxed with 50 cm3 of 1 mol dm-3 aqueous NaOH and all ammonia gas evolved is expelled. The resulting solution is subsequently titrated with 1 mol dm-3 H2SO4 solution.

What is the volume of H2SO4 required for complete neutralisation of the resulting solution?

A 10 cm3 C 30 cm3

B 20 cm3 D 40 cm3



21 Which compound can be synthesized from prop-1-ene in less than 3 steps?

A

C

H

C

H

H

H CH3

N C

O

C

H

H

H

H

C

CC

H

H

H

C

O

OH

O

B

C

OH

C

H

H

H CN

C

H

H

H

D

C

H

C

H

H

H CH3

C N

H

H

H

H


22 In the presence of a base, some aldehyde and ketone undergo a rapid and reversible condensation reaction, where they dimerise to form a hydroxycarbonyl compound (an aldol).

This reaction is initiated by the production of the enolate ion, RCOCH2–, formed

from the reaction between a carbonyl molecule and a base.

What is the mechanism involved in the above reaction?

A Electrophilic addition C Nucleophilic addition

B Electrophilic substitution D Nucleophilic substitution



23 A mixture of amino acids can be separated by electrophoresis.

filter paper Mixture of amino acids

The following information about alanine and two other amino acids are given as below.

Amino acid Structure Isoelectric point

alanine (ala)

C

H

H2N

CH3

COOH

6.01

glutamine (gln)

C

H

H2N

CH2CH2CONH2

COOH

5.65

lysine (lys)

C

H

H2N

(CH2)4NH2

COOH

9.74

Which of the following filter papers show a possible result of the separation of the amino acid mixture at pH 8?


A

anode cathode

lys gln ala

B

anode cathode

ala gln lys

C

anode cathode

lys ala gln

D

anode cathode

lys gln ala


24 In which of the following sequences does the value of pKa increase continuously?

A CH3CHClCOOH, CH3CH2COOH, C6H5OH

B CH2ClCH2COOH, CH3CHClCOOH, CH3CH2COOH

C C6H5OH, CH3CHClCOOH, CH3CHFCOOH

D CH3CH2COOH, CH3CHFCOOH, CH3CF2COOH



25 Enols, also known as alkenols, are alkenes with a hydroxyl group affixed to one of the carbon atoms composing the double bond. Enols and carbonyl compounds are rapidly interconvertible via a process called tautomerism.

C

O

CH

C

O

C

H

rapid equilibration

enolcarbonyl compound

The enol form is usually unstable and difficult to isolate and are present only to a very small extent at equilibrium. Propane-1,2-diol can undergo dehydration with excess concentrated H2SO4 to give enols and a mixture of products. Which of the following is false about the resulting solution?

A It decolourises hot acidified potassium manganate (VII) solution with the evolution of a colourless gas.

B It gives a yellow precipitate with aqueous alkaline iodine.

C It gives a grey precipitate with silver diammine complex.

D It reacts with cold alkaline potassium manganate (VII) solution to give an optically active product.


26 Which of the following statements is false?

A Denaturation does not affect the primary structure of proteins which implies that there is no breakage of the peptide bonds.

B In an alpha helix, the amide carbonyl oxygen of an amino acid residue n is hydrogen bonded to the amide hydrogen of residue n+4.

C The formation of the peptide link between amino acids is irreversible.

D The quaternary structure only applies to proteins that contain two or more polypeptide chains.


•

CJC/PRELIM 2009/P1/Q19 Athletes preparing for the Youth Olympics Games (YOG) in 2010 follow a high-carbohydrate diet to maintain high-intensity exercise for a longer period.

Glucose is an important carbohydrate in biology as the living cell uses it as a source of energy and metabolic intermediate.

glucose

How many stereoisomers does glucose exhibit?

A 21 B 22 C 23 D 24 CJC/PRELIM 2009/P1/Q20 20 The equation below represents the sulfonation of benzene under suitable

conditions.

+ H2SO4 + H2O

What is the role of concentrated sulfuric acid in the reaction? A a dehydrating agent B an electrophilic agent

C a nucleophilic agent D an oxidising agent CJC/PRELIM 2009/P1/Q21 21 Chlorofluorocarbons, commonly known as CFCs, undergo homolytic fission by

ultraviolet irradiation in the stratosphere. Which radical could result from this irradiation of CHFClCF2Cl?

A CHFClCFCl

B •CHClCF2Cl

C •CHFCF2Cl

D •CFClCF2Cl

SO3H


C C

H

Cl H

Cl

HH

CJC/PRELIM 2009/P1/Q22 22 A product P, isolated from a naturally-occurring source, has a molecular formula

of C9H11NO3. It possesses a chiral centre and it forms a zwitterion. What could the structure of P be?

A B C D

CJC/PRELIM 2009/P1/Q23 23 Which of the following compounds is not an addition product of the reaction

between ethene with aqueous chlorine in the presence of sodium bromide?

A B

C D

CJC/PRELIM 2009/P1/Q24 24 Which of the following compounds could be prepared by reacting chloropropane

with potassium cyanide and then reducing the product? A CH3CH2CH3

B CH3CH2CH2NH2

C CH3CH2CH2CH3

D CH3CH2CH2CH2NH2

O2N CH2CH(OH)CH3 HO CH2CH(NH2)CO2H

HO2C CH2CH2NH2 CH3 CH2CO2H

C C

H

Br H

OH

HH

C C

H

Br H

Cl

HH

C C

H

Cl H

OH

HH


CJC/PRELIM 2009/P1/Q25 25 In the preparation of ethene, ethanol is added a drop at a time to heated reagent

Y. The impure ethene is washed by being bubbled through a solution Z and then collected.

What are the reagent Y and solution Z likely to be?

CJC/PRELIM 2009/P1/Q26 26 The following reaction scheme shows the formation of compound C. What is the structure of compound C?

A B C D

reagent Y solution Z

A acidified K2Cr2O7 dilute NaOH

B acidified K2Cr2O7 dilute H2SO4

C concentrated H2SO4 dilute NaOH

D concentrated H2SO4 dilute H2SO4

heat

NaOH(aq)

NCCH2CHClCH2 CH2CONH2

Cl

B C 1. H

+(aq) NaOH(aq)

2. PCl5

NCCH2CH(OH)CH2 CH2COCl

Cl

NCCH2CHClCH2 CH2CONH2

OH

ClOCCH2CH(OH)CH2 CH2CONH2

OH

ClOCCH2CHClCH2 CH2COCl

Cl


CJC/PRELIM 2009/P1/Q27 27 Which of the following reagents will give similar results for both butanone and

ethanol? A acidified aqueous potassium dichromate(VI)

B iodine and aqueous potassium hydroxide

C Fehling‟s solution

D 2,4-dinitrophenylhydrazine reagent

CJC/PRELIM 2009/P1/Q28 28 Which of the following reagents is least likely to react with vitamin C?

A 2,4-DNPH

B Na metal

C SOCl2

D Br2(aq)

CJC/PRELIM 2009/P1/Q29 29 Which of the following could be a correct synthesis of aspirin, as shown below?

OCOCH3

CO2H

aspirin

A

OO

OHHO

OH

OH Vitamin C


OCOCH3

CO2CH

3

OCOCH3

CO2Na

OCOCH3

CO2H

NaOH(aq)

reflux

HCl(aq)

B

OH

CO2H

OCOCH3

CO2H

CH3COCl+ HCl

C

OH

CO2H

OCOCH3

CO2H

conc H2SO4

reflux

+ H2O+ CH3OH

D

OCOCH3

CN

OCOCH3

CO2Na

OCOCH3

CO2H

NaOH(aq)

reflux

HCl(aq)


CJC/PRELIM 2009/P1/Q30 30 A useful oxidising agent specifically for vicinal diols (ie. the two OH groups are on

adjacent carbons) used in the laboratory includes NaIO4. An example of the

conversion using butane-2,3-diol is shown below:

What would be the final organic products obtained when compound Y is first

treated with cold alkaline aqueous KMnO4 followed by NaIO4?

Compound Y is CH3CH=C(CH3)–CH2–CH=CH(CH3)

A B

C

D

CH3 C C

CH3

C

O O

H

CH2H

O

+

CH3 C C C

O O

H

CH2H

O

+H

CH3 C C C

O

HCH2H+ H

H

OH OH

CH3

CH3 C C C

O

H

CH2+ H

H

OHO

H

C C CH3CH3

OH OH

H H

NaIO4CCH3

O

H

2



JJC/PRELIM 2009/P1/Q20 20. The structure of compound X is given below.

How many new chiral centers will be formed when Compound X is completely hydrogenated over a nickel catalyst?

A 2

B 3

C 6

D 7

JJC/PRELIM 2009/P1/Q21 21. When ethene reacts with bromine in the presence of concentrated aqueous sodium

nitrate, one of the products formed is given below.

What is the intermediate formed in this reaction?

A

C

H

C H

H

H

Br

C

ONO2

H H

H H C C C C

H H

H H

Br ONO2

Compound X

– +


B

D

JJC/PRELIM 2009/P1/Q22 22. How many isomers (both structural and stereoisomers) are possible for an aromatic

compound of molecular formula C8H7Cl?

A 4

B 5

C 6

D 7

JJC/PRELIM 2009/P1/Q23

23. Bromine-containing organic compounds, X, Y and Z, are added to aqueous silver nitrate. The mass of cream precipitate formed is measured after some time.

Compound Mass / g

X 0

Y 0.15

Z 1.05

Which of the following gives the correct structures for X, Y and Z?

X Y Z

A BrCH2CH2Br C6H5Br BrCH2CH2COBr

B C6H5Br BrCH2CH2COBr BrCH2CH2Br

C C6H5Br BrCH2CH2Br BrCH2CH2COBr

D BrCH2CH2COBr BrCH2CH2Br C6H5Br

ONO2

C C

H H

H H

H H

H H C C

Br + –



24. Which compound reacts with 2 moles of aqueous sodium hydroxide at room temperature?

A B C D

JJC/PRELIM 2009/P1/Q25 25. Compound X, C6H12O, is oxidised by acidified sodium dichromate(VI) to compound Y.

Compound Y reacts with ethanol in the presence of a little concentrated sulphuric acid to give liquid Z. What is the formula of Z?

A CH3(CH2)2CH=CHCO2H

B CH3(CH2)4CH2COCH2CH3

C CH3(CH2)4CO2CH2CH3

D CH3CH2CO2(CH2)4CH3


26. The anti-bacterial drug tetracycline has the formula

tetracycline

CH2OH

CH2OH

OH

OH

COOH HCOO

OH

CH2Br

HCOO OH

COOH

CH2OH


Which statement about tetracycline is correct?

A It does not react with SOCl2.

B It reacts with sodium carbonate to liberate carbon dioxide gas.

C 3 moles of HBr is formed when 1 mole of tetracycline reacts in an excess of aqueous bromine in the dark.

D It reacts with sodium metal to liberate H2 gas. JJC/PRELIM 2009/P1/Q27 27. A nitrile X undergoes the following two reactions:

What would be produced when the products from the two reactions are mixed together?

A [ CH3CH2NH3+ ] [CH3CH2CO2– ]

B [ CH3CH2NH3+ ] [CH3CO2

– ]

C CH3CONHCH2CH3

D CH3CH2CONHCH2CH3

Nitrile X

Product, CH3CH2NH2

Product

reduction acid

hydrolysis


JJC/PRELIM 2009/P1/Q28 28. Compound Q was subjected to the following tests and the results are recorded below.

Reagents & Conditions Observations

Acidified KMnO4, heat Solution turns from purple to colourless. A gas is evolved.

Fehling‟s reagent, heat No precipitate observed

Tollens‟ reagent, heat Silver mirror observed

What could Q be?

A B C D

JJC/PRELIM 2009/P1/Q29 29. The structures of P, Q and R are shown below.

When equal amounts of P, Q and R (not necessarily in that order) are added to separate portions of water, solutions with pH values of 2.5, 3.0 and 3.5 are formed. Deduce which pH value is associated with each of the compounds P, Q and R.

pH 2.5 pH 3.0 pH 3.5

A Q P R

B P Q R

C R Q P

D R P Q

CH2COOH CHClCOOH CHFCOOH

P Q R

CHO

CH=CH2

COCH3 CH2CHO

CH2OH

CO2H

OH


JJC/PRELIM 2009/P1/Q30 30. Gastrins are heptadecapeptide (17 amino acid units) hormones that stimulate the

secretion of gastric acid in the stomach of mammals. On hydrolysis of gastrins, the following four peptide fragments were isolated. gly-trp leu-glu-glu-glu-glu-ala-ala-try glu-gly-pro-trp met-asp-phe C-terminus analysis of the heptatdecapeptide yields a phe residue while N-terminus analysis yields a glu residue. Based on the information above, suggest a primary structure for the heptatdecapeptide and the number of peptide bonds it contains.

Primary Structure No. of peptide

bonds A glu-gly-pro-trp-gly-trp-leu-glu-glu-glu-glu-ala-ala-try-met-asp-phe 17

B glu-gly-pro-trp-gly-trp-leu-glu-glu-glu-glu-ala-ala-try-met-asp-phe 16

C phe-asp-met-gly-trp-leu-glu-glu-glu-glu-ala-ala-try-trp-pro-gly-glu 16

D phe-asp-met-gly-trp-leu-glu-glu-glu-glu-ala-ala-try-trp-pro-gly-glu 17

22 Compound P is optically active.

O

OH

Cl

CH3

P

How many chiral centre(s) does compound P have?

A 1

B 2

C 3

D 4


DHS/PRELIM 2009/P1/Q23

23 A student attempts to synthesise compound S from the following synthetic route.

1. Br2/H

2O

2. KCN, base CN

H2/Ni

S

Which of the following could be compound S that is formed in this reaction?

A

CN

B CH2NH2

C

CN

D CH2NH2


24 An alcohol X, when treated with hot acidified aqueous potassium manganate(VII), gives a final oxidation product which reacts positively to the tri-iodomethane (iodoform) reaction. Which one of the following formula could be X?


A

OH

B C2H5OH

C CH3CH(OH)C2H5

D C6H5CH(OH)C2H5


25 Which one of the following represents the organic ion produced when an excess of hot aqueous sodium hydroxide is added to compound R?

ClH2C

COOCH3

OCOCH3

R

A

O-

COO-

HOH2C

B OH

COO-

O-H2C

C COO

-

O-

HOH2C

D COO

-

OH

O-H2C


26 Which one of the following, in alcoholic solution, produces a precipitate most rapidly when warmed with aqueous silver nitrate?

A chlorobenzene

B 1-iodobutane

C 1-bromobutane

D 1-chlorobutane



27 What is the total number of possible stereoisomers that can be formed when the following compound reacts with excess concentrated H2SO4?

OH

OH Cl

A 2

B 4

C 6

D 8


28 Compound Q is subjected to the following tests and the results are recorded below.

reagents and conditions observations

acidified KMnO4 and reflux Purple solution turns colourless. Effervescence of colourless gas.

Fehling‟s reagent and warm No precipitate seen.

Tollen‟s reagent and warm Silver mirror is formed.

Which of the following could be compound Q?

A CHO

CHCH2

B CH3O


C COOH

CH2OH

D

OH

O

H


29 The reduction of a nitrile produces a compound of formula C3H7NH2. Which of the following would be produced if the same nitrile is heated with hydrochloric acid?

A CH3CONH2

B CH3CH2OH

C CH3CH2COOH

D (CH3)2CHCOOH


30 Separation of benzene from a mixture of benzene and an organic amine could involve

A Treating the mixture with dilute aqueous alkali.

B Treating the mixture with dilute aqueous acid.

C Extracting the amine with cyclohexanol.

D Extracting the benzene with diethyl ether (CH3CH2OCH2CH3).

HCI/PRELIM 2009/P1/Q21

21 Spironolactone is an anti-androgen used as a common component in hormone therapy.


O

O

O

OH3C

CH3

H3C

How many stereoisomers does spironolactone have?

A 23 B 24 C 26 D 27


22 Which of the following compounds will not be produced when propene reacts with a mixture of Br2 in aqueous NaCl?

A H3C C C H

H

Br

H

Br

C H3C C C H

H

Cl

H

Br

B H3C C C H

H

Cl

H

Cl

D H3C C C H

H

Br

H

Cl


23 During electrophilic substitution on a benzene ring, the position of the incoming group, the new substituent, is determined by the nature of the group(s) already present in the ring. The directing effects of these groups are shown in the table below.

Directing Effects 3 – directing 2,4 – directing

Functional Groups with these

effects –NO2, –CO2H,

–CH3, –NH2, –X (halogens)

Compound V may be synthesised from benzene.

Br

HO2C NH2


V Which of the following synthetic routes will yield compound V?

A Nitration alkylation reduction bromination oxidation B Alkylation nitration oxidation bromination reduction C Bromination nitration reduction alkylation oxidation D Nitration reduction bromination alkylation oxidation


24 The table below shows the rate of hydrolysis of the halogen-containing compounds P to S. The rate of hydrolysis is measured by the speed at which the silver halide precipitate is formed.

P Q R S

Cl

CH2Cl

CH2Br

CH2I

No precipitate formed with prolonged heating with ethanolic AgNO3.

Precipitate formed after 10 minutes of heating reaction mixture with ethanolic AgNO3.

Precipitate formed after 2 minutes of warming reaction mixture with ethanolic AgNO3.

Precipitate forms instantaneously with ethanolic AgNO3.

Which statement explains the rate of reaction?

A The C–X bond length increases from compound P to S. B The solubility of the compounds increases from P to S. C The mechanism for the reaction changes from P to S. D The reaction conditions are increasingly milder from P to S.


25 Which of the following deductions about the reactions of G can be made from its structure?


O

OH

O

CH3

G

A It gives white fumes of HCl with PCl5. B It gives a yellow precipitate with aqueous alkaline iodine. C It gives an orange precipitate with 2,4-dinitrophenylhydrazine. D It gives a violet colouration with neutral FeCl3 solution.


26 Which of the isomers of C6H14O2 gives, on complete dehydration, the greatest number of isomers, including stereoisomers?

A CH3 CH2 CH CH CH2 CH3

OHOH

B CH3 C C CH3

OHOH

CH3CH3

C CH3 CH2CH CH CH2 CH3

OHOH

D CH3 CH2CH

OH

CH3CH2 CH

OH


27 A compound U has all the following properties: - It is neutral. - It gives a silver mirror with Tollens' reagent.


- It decolourises a hot aqueous solution of acidified KMnO4 with evolution of CO2 gas. What could U be?

A COCH3

CH(OH)CH3

B CHO

OCH3

C

C

OH

OCH3

O

D CH(OH)CH3

CH2CHO


28 Which reaction yields a carbon compound incorporating deuterium, D? [D = 2H]

A CH3CH2CN

NaOD

D2O

B CH3CD2OHacidified KMnO4

heat

C CH3COCH3

LiAlD4

dry ether

D (CH3)3COHconc. D2SO4

heat


29 The sesquiterpene lactone, M, extracted from sunflowers, was studied to determine its anti-tumour potency.

O

NNH

O

O

CH3

O

CH3

CH2

CH3CO2


M

How many moles of dilute NaOH are required to completely hydrolyse 1 mole of M?

A 3 B 4 C 5 D 6


30 A student attempted to synthesize the following compound N.

OCOCH3

NHCOCH3

N

Which of the following pairs of reactants will give the target molecule?

A OH

COCl

and CH3NH2

C OH

NH2

and CH3CO2H

B OH

NH2

and CH3COCl

D CO2H

NH2

and CH3COCl

MI/PRELIM 2009/P1/Q23 The compound CF3CHBrCl is a general anaesthetic called halothane. The number of structural isomers, including halothane, having the molecular formula C2HBrClF3 is

A 2 B 3 C 4 D 5

MI/PRELIM 2009/P1/Q24 Which one of the following sequences of nitration, alkylation and bromination is expected to give the best yield for the synthesis of 2–bromo–4–nitromethylbenzene from benzene?

A Alkylation, nitration, bromination B Alkylation, bromination, nitration C Nitration, alkylation, bromination D Nitration, bromination, alkylation

MI/PRELIM 2009/P1/Q25 The structure below shows the active ingredient of a certain drug.


Which one of the following statements is FALSE about this compound? A It has 4 stereoisomers. B It gives white fumes with PCl5. C One molecule of this compound reacts with 3 molecules of bromine. D Complete hydrolysis of this compound gives CH3NH2 as one of the

product. MI/PRELIM 2009/P1/Q26 Which one of the statements about the following ester is correct?

A It is a chain isomer of pentanoic acid. B It is a functional group isomer of ethyl propanoate. C It can be hydrolysed to produce an alcohol that is resistant to oxidation by

acidified potassium dichromate(VI). D It can be hydrolysed to produce an alcohol that can also be formed by the acid-catalysed hydration of propene. MI/PRELIM 2009/P1/Q27 Which one of the following is formed when an excess of bromomethane reacts with diethylamine?


MI/PRELIM 2009/P1/Q28 A sequence of reactions is shown below.

A correct list of substances for the sequence is

Reaction 1 Reaction 2 Reaction 3 Reaction 4

A CH3COCl NaBH4 Conc. H2SO4 Cl2

B AlCl3 HCl NaOH Cl2

C AlCl3 NaBH4 Conc. H2SO4 HCl


D AlCl3 NaBH4 Conc. H2SO4 Cl2

MI/PRELIM 2009/P1/Q29 One industrial preparation of ethanoic acid is direct carbonylation of methanol, using a rhodium catalyst.

CH3OH +CO rhodium

CH3CO2H

Which compound could be expected to produce by this method?

A B C D

MI/PRELIM 2009/P1/Q30 Gastrins are hexadecapeptide (16 amino acid units) hormones that stimulate the secretion of gastric acid in the stomach of mammals. On hydrolysis of gastrins, the following four peptide fragments were isolated.

H2N–gly–trp–CO2H H2N–leu–glu–glu–glu–ala–ala–try–CO2H H2N–glu–gly–pro–trp–CO2H H2N–met–asp–phe–CO2H

C–terminus analysis of the hexadecapeptide yields a phe residue while N–terminus analysis yields a glu residue. Based on the information above, suggest a primary structure for the hexadecapeptide and the number of peptide bonds it contains.

Primary structure No. of

peptide bonds

A H2N–glu-gly-pro-trp-trp-gly-leu-glu-glu-glu-ala-ala-try-met-asp-phe–CO2H 15

B H2N–glu-gly-pro-trp-gly-trp-leu-glu-glu-glu-ala-ala-try-met-asp-phe–CO2H 15

C H2N–glu-gly-pro-trp-gly-trp-leu-glu-glu-glu-ala-ala-try-met-asp-phe–CO2H 16

D H2N–phe-asp-met-try-ala-ala-glu-glu-glu-leu-trp-gly-trp-pro-gly-glu–CO2H 16

HC

CO2H

CH2CO2H

CH2CO2H

HC

CO2H

CO2H

OH

HC

CH2OH

CH2CO2H

CH2CO2H

HC

CO2H

CH2CO2H

OH

HC

CH2OH

CH2CO2H

OH


NJC/PRELIM2009/P1/Q18

How many isomeric carbonyl compounds with molecular formula C5H10O are there? A 7

B 8

C 9

D 10


Trichloroethene is widely used as dry-cleaning agent.

Cl

ClCl

H Trichloroethene

Which of the following does trichloroethene react with to give a chiral product? A Br2

B HCl

C NaOH

D NaCN


The oxo-reaction is an important industrial process in which an alkene combines directly with carbon monoxide and hydrogen under suitable conditions. The reaction with ethene is shown below. CH2=CH2 + CO + H2 CH3CH2CHO Which of the following structural formula correctly represents the product of the oxo-reaction starting with but-2-ene ? A CH3CH2CH(CH3)CHO

B CH3CH2CH2CH2CHO

C CH3CH2COCH2CH3

D CH3COCH2CH2CH3

Catalyst High T, p



Which is the major product for the following reaction?

CH3

NO2+ AlCl3 Cl2+

A

CH3

NO2

Cl

CH3

NO2

Cl

B CH3

NO2

Cl

CH2Cl

NO2


Which of the following will not be produced when 1-chloropropane is heated in ethanolic sodium hydroxide? A CH3CH=CH2

B CH3CH2CH2OH

C CH3CH2CH2ONa

D CH3CH2CH2OCH2CH3

C

D



Which sequence correctly represents the compounds in the order of increasing pKa values? A

C

Cl

OH

H

OH

CH3

OH

Cl

B

C

Cl

OH

H

OH

CH3

OH

Cl

C

C

Cl

OH

H

OH

CH3

OH

Cl

D

C

Cl

OH

H

OH

CH3

OH

Cl


How many chiral centres are present in the major product formed when compound S undergoes a reaction with KBr and concentrated H2SO4 at high temperature?

CH3

HO

CH3

H3C

S

A 6

B 7

C 8

D 9



Compound P is used in the following synthesis.

COCH2CH2OH

CH2OH

D E

excess conc. H2SO4

heat

Br2(aq)

P What is the likely structure of the final product R? A

COCHOHCH2BrBr

Br

CH2OH

COCHBrCH3

CH2OH

B

COCHBrCH2Br

CH2OH

Br

COCHOHCH2Br

CH2OH


Compound N is a product formed from the reaction between an alcohol and hot acidified potassium manganate(VII). Compound N

gives no yellow precipitate with alkaline iodine

evolves a colourless gas when treated with aqueous sodium carbonate

reacts with 2 moles of PCl5 to give white fumes What is the structural formula of the alcohol? A CH3COCH2CH2COOH

B CH3CH(OH)CH2CH2CH2OH

C (CH3)2C(OH)CH2COOH

D (CH3)2C(OH)CH2CH2OH

C

Q R

D

COCH(OH)CH2Br

COCH(OH)CH2Br



The mechanism below shows how butanone reacts with hydrogen cyanide. Which statement is true? A The product mixture is optically active.

B Rate of reaction increases when butanone is substituted with butanal.

C Cyanohydrin produced can react with ammonia at high pressure to form amine.

D Cyanohydrin produced requires potassium manganate(VII) to form carboxylic acid .


Phenylalanine is used to synthesize compound M during the production of a drug. Which of the following can be used to identify the phenylalanine from compound M?

CH2CHCOOH

NH2

CH2CHCHCOOH

NH2

OH

Phenylalanine M A Sodium metal

B Phosphorus pentachloride

C Aqueous sodium carbonate

D Hot acidified potassium dichromate(VI)

C O

H3C

+ CN-+ -CH3C

CH2CH3

O-

CN

CH3C

CH2CH3

O-

CN

+ H CN+ - CH3C

CH2CH3

OH

CN

+ CN-

slow

CH2CH3



Which synthetic route will lead to a successful synthesis of the following product?

COOH

CH2CH2CH3 A COOH

CH2CH2CH3

CH2OH

CH2CH2CH3

CHO

CH2CH=CH2

CHO CH2=CHCH2Cl

AlCl3

LiAlH4 in

dry ether

K2Cr2O7

dilute H2SO4

heat

B COOH

CH2CH2CH3

CH2OH

CH2CH2CH3

CHO

CH2CH=CH2

CHO CH2=CHCH2Cl

AlCl3

LiAlH4 in

dry ether

KMnO4

dilute H2SO4

heat

C COOH

CH2CH2CH3

CH2OH

CH2CH2CH3

CHO

CH2CH=CH2

CHO CH2=CHCH2Cl

AlCl3

H2 / Pt KMnO4

dilute H2SO4

heat

D COOH

CH2CH2CH3

CH2OH

CH2CH2CH3

CHO

CH2CH=CH2

CHO CH2=CHCH2Cl

AlCl3

H2 / Pt K2Cr2O7

dilute H2SO4

heat


Electrophoresis is a technique of separating and identifying amino acids. A solution of amino acids is absorbed into paper that is moistened with a buffer solution and stretched between two electrodes. Positively charged species move towards the cathode, negatively charged species towards the anode. With a buffer at pH 4, which amino acid will move most readily towards the cathode? A

C O

NH2OH

OH

O

O

NH2

NH2

OH


B

NYJC/PRELIM2009/P1/Q21

The following statements were made about the structure and functional groups of compound P

OH

OH CH(OH)CH 2OH

Compound P

I. It has cis-trans isomers II. It is optically active III. It has three chiral centres

Which of the above statement(s) about compound P is/are correct? A I, II and III

B I and II only

C II and III only

D II only


Which of the following isomers of C5H11Br gives the greatest number of

different alkenes on treatment with hot ethanolic sodium hydroxide?

A CH3CH2CH(CH3)CH2Br

B CH3CH2CH2CHBrCH3

C CH3CH2CHBrCH2CH3

D CH3CH(CH3)CH2CH2Br

D O

NH2

N

NH

OH

O O

OHOH

NH2



Which one of the following reagents will distinguish X and Y?

HO

OCH3

HO

O

O

CH3

CH3 CO

O

CH2OH

OH

A aqueous bromine

B Fehling‟s reagent

C phosphorus pentachloride

D alkaline aqueous iodine


Vanillin is the main constituent of vanilla flavouring. OH

CHO

OCH3

What is the product of its reaction with KMnO4 in aqueous KOH? A O

-K

+

CO2

- K

+

OCH3

B O-K

+

COOH

OCH3

X Y


C OH

COOH

OCH3

D O-K

+

CHO

OCH3


The 1st stage of the cumene process for the industrial production of phenol is as follows:

+ CH3 CH CH2

H2 SO

4

CH

CH3CH3

Which one of the following would be the product of the reaction under similar conditions between benzene and cyclohexene?

A

B

C

CH2(CH2)4CH3

D

CH CH(CH2)3CH3


The reddish brown colour of aqueous bromine is discharged when a solution of phenylamine is added to it. Which statement explains this observation?

A Bromine displaces hydrogen in the benzene ring

B The NH2 group of phenylamine is substituted by bromine

C Bromine forms a colourless complex with phenylamine

D Phenylamine oxidizes Br2 to Br -


Which one of the following is a product of the reaction between phenylmethanol, and ethanoyl chloride, CH3COCl ?


A OCOCH3

B CH2OCOCH3

C COOCH2CH3

D CH2COOCH3


One industrial preparation of ethanoic acid is the direct carbonylation of methanol using a rhodium catalyst

OHCH3 + COrhodium

catalystCH3 C

OH

O

Which compound could be expected to produce

CH

CO2H

CH2CO2H

CH2CO2H ? A

CH

OH

CO2H

CH2OH

B

CH

CH2OH

CH2CO2H

CH2CO2H

C CH

OH

CH2CO2H

CO2H

D

CH

OH

CH2CO2H

CH2OH



It has been reported that some cases of acute liver failure could have been caused by an overdose of Paracetamol. Which of the following statements about Paracetemol is incorrect?

Paracetemol

A It reacts with hot, aqueous sodium hydroxide to give sodium ethanoate

B There is no yellow precipitate observed on adding aqueous, alkaline iodine

C The colourless gas evolved on adding sodium metal extinguished a lighted splinter with a “pop” sound.

D An aqueous solution of Paracetamol is alkaline


What is the order of increasing pKb for the following compounds?

NH

2NH

2

NO2

NHCH3 NH

2

I II III IV

A II, I, III, IV

B IV, III, I, II

C III, IV, II, I

D III, IV, I, II

NH C

HO

O

CH3


PJC/PRELIM2009/P1/Q21

















RIJC/PRELIM2009/P1/Q19

















SAJC/PRELIM2009/P1/Q23

Which of the following pairs of compounds can be attacked by cyanide ions via

nucleophilic reactions?

A CH3CH2Cl and CH3COCH2CH3

B CH3CH2Cl and CH3COOCH3

C C6H5Cl and CH3COCH2CH3

D C6H5Cl and CH3COOCH3


Acarol is the active ingredient in many insecticides.

Br

C

HO C

O

O C(CH3)3

Br

Acarol

Which of the following statements about Acarol is true?

A Acarol exhibits stereoisomerism.

B Acarol forms white fumes with thionyl chloride.

C Acarol changes hot, acidified K2Cr2O7 from orange to green.

D Acarol forms an orange precipitate with 2,4 dinitrophenylhydrazine.


Cannabis is a psychoactive drug which accumulates in the fatty tissues of the body.

Compound W can be prepared from cannabis as shown in the following reaction

sequence.


CH3

HO (CH2)4CH3

OH

C CH3

H2C

Cannabis

CH3

-O (CH2)4CH3

C CH3

H2C

O-Step I

CH3

HOOC(CH2)2O (CH2)4CH3

C CH3

H2C

O(CH2)2COOH

Step II

W

Which of the following reagents can be used to prepare compound W?

Step I Step II

A Na2CO3 CH2(OH)CH2COOH

B NaOH CH2ClCH2COOH

C Na CH2(OH)CH2CH2COOH

D NaOH CH2ClCH2CH2COOH


When propene reacts with Br2 in the presence of excess aqueous KNO3, what are the

two major products formed?

A H C C C

H

H

H

Br

H

H

Br

and H C C C

H

H

H

OH

H

H

Br

B H C C C

H

H

H H

H

BrH

and H C C C

H

H

H

OH

H

H

Br


C and H C C C

H

H

H H

H

OHBr

H C C C

H

H

H H

H

HBr

D H C C C

H

H

H H

H

Br

ONO2

and H C C C

H

H

H

OH

H

H

Br

SAJC/PRELIM2009/P1/Q27 Which of the following reactions would not produce 1,3-dicarboxylic acid?

A

CHO

CHO

+ Fehling's solution followed by acidification

B

C

COOCH3

H

CH2CH3

+ hot acidified potassium manganate (VII)

C

CN

COOCH3

+ aqueous H2SO4, reflux


D

CH(OH)CH3

COCH3

+ alkaline aqueous iodine followed by acidification


The diagram represents a section of a catalytic converter on the exhaust system of a

car. Harmful gases are converted into carbon dioxide, nitrogen and water vapour.

COHydrocarbonsNOx

CO2

H2O

N2

Platinum and Rhodium catalyst

Which statement about the catalytic convertor is not true?

A NOx are reduced to N2 by the excess CO present.

B Cars fitted with a catalytic converter may run on leaded petrol.

C Platinum and rhodium catalyse redox reactions.

D Platinum and rhodium are coated on a ceramic honeycomb structure so as to

maximise surface area.


The amino acids lysine and glutamine can react with each other to form peptide

linkages.

H2N C COOH

H

CH2CH2CH2CH2NH2

H2N C COOH

H

CH2CH2CONH2

lysine glutamine

What is the maximum number of different compounds, each containing one peptide

linkage that can be formed from one molecule of lysine and one molecule of glutamine?

A 2

B 3


C 4

D 5


X possesses a chiral centre and forms a zwitterion. Which one of the following structures

could X be?

A

OH

COOH

H3C

NH2

B

NH2

CH2OHHOOC

C

CHOH(CH3)

NO2

D

HO

CH

NH2

COOH

SRJC/PRELIM2009/P1/Q22

Identify the number of sp2 and sp3 hybridised carbon atoms in the given

structure:

C C C H

H H O

sp2 sp3

A 2 5

B 3 4

C 8 5



Which of the following is the propagation step in the reaction between

ethane and bromine in the presence of ultraviolet light?

A Br2 2Br

B CH3CH2 + Br CH3CH2Br

C CH3CH2 + HBr CH3CH2Br + H

D CH3CH2 + Br2 CH3CH2Br + Br SRJC/PRELIM2009/P1/Q24



D 9 4

Ethene reacts with bromine to form dibromoethane. Which of the following

best describes the organic intermediate in this reaction?

A The shape about each carbon in the intermediate is trigonal planar.

B It has a negative charge.

C It is an electrophile.

D It is a free radical.

Which sequence shows the increasing ease of hydrolysis?

A C6H5Br > C6H5CH2Cl > CH3CH2COCl > CH3CH2I

B CH3CH2COCl > CH3CH2I > C6H5CH2Br > C6H5CH2Cl

C C6H5Cl > CH3COCH2Cl > C6H5CH2Br > CH3CH2I

D C6H5Br > CH3CH2Cl > C6H5CH2I > CH3CH2COCl

Which reagent could be used to distinguish between pentan-2-ol and

pentan-2-one?





A aqueous bromine

B alkaline aqueous iodine

C acidified potassium manganate(VII)

D sodium carbonate

A 3-step reaction scheme is shown below.

CH2Br CH2OH

CH3 CH3

C

CH3

O

H C

CH3

OH

CNH

I II III

Which one of the following correctly describes the types of organic reactions for steps I and III?

Step I Step III

A Electrophilic substitution Nucleophilic addition

B Electrophilic substitution Electrophilic addition

C Nucleophilic substitution Nucleophilic addition

D Nucleophilic substitution Electrophilic substitution

An ester G has the following chemical formula: C3H7COOC3H7 Which pair of compounds can be produced when G is refluxed with dilute sulphuric acid?

A CH3CH2CH2COOH and (CH3)2CO

B (CH3)2CHCOOH and CH3CH2CH2OH

C CH3CH2COOH and CH3CH2CH2OH

D (CH3)2CHCOCl and (CH3)2CHOH

Partial hydrolysis of insulin, the hormone essential for carbohydrate metabolism gives the following tripeptide.

Oxidation



TPJC/PRELIM2009/P1/Q18


CH2CH2CO2H │ (CH3)2CHCH(NH2)CONHCHCONHCH(CH3)CO2H Insulin Which compound could be obtained by further hydrolysis of this tripeptide?

A CH3CH(CO2H)2

B (CH3)2CHCH(NH2)CONH2

C H2NCONHCH(CH2CH2CO2H)CO2H

D H2NCH(CH2CH2CO2H)CONHCH(CH3)CO2H

The painkiller Phenacetin can be made as follows:

NH2

OCH2CH3

NHCOCH3

OCH2CH3

Phenacetin

What could be the reagent J?

A CH3CH2NH2

B CH3COCH3

C CH3COOH

D CH3COCl

Reagent J


















VJC/PRELIM2009/P1/Q19

The hydride ion, H-, is a strong reducing agent, a good nucleophile and a good base. Which one of the following conversions would the hydride ion not be expected to bring about?

A C2H5Br to C2H6

B CH3CH3 to CH2=CH2

C CH3CHO to CH3CH2OH

D CH3CO2H to CH3CO2-


2,2-dimethylpropane reacts with chlorine gas in the presence of ultraviolet light to give a mixture of products. Which one of the following statements is correct regarding this reaction?

A Only one mono-substituted product is formed.

B Only the propagation step involves C-Cl bond formation.

C Only the initiation step of the mechanism involves homolytic fission.

D Both propagation and termination steps produce hydrogen chloride.


Which one of the following cannot be made directly from methylbenzene?

A B C D



Nootkatone is one of the organic compounds found in grapefruit. Its structure is as shown below.

Which statement is correct about nootkatone?

A It forms a pale yellow precipitate with alkaline I2(aq).

B It reacts with Tollen‟s reagent to give a silver mirror.

C It reacts with potassium cyanide in ethanol to form a nitrile compound.

D It reacts with hot acidified potassium manganate(VII) to form one organic product.


An organic compound X undergoes the following reactions:

(i) It decolourises a solution of bromine in tetrachloromethane.

(ii) It reacts with phosphorus pentachloride giving copious white fumes

of HCl.

(iii) It reacts with hot alkali to give a compound with two alcohol

functional groups.

Which compound could be X?

A HOH2CCH=CHCH=CHCH2Cl

B Cl2CHCH=CHCH2COOH

C BrCH2CH2CHClCH2COCl

D ClCH2CH2CH=CHCH(Cl)CH2OH



Which process will not give a good yield of CH3CO(CH2)3CO2H?

A

Hot KMnO4(aq), H3O+KOH in ethanol

heat

CH3

Cl

B

KOH(aq)H2NCO(CH2)3CHClCH3

Hot KMnO4(aq), H3O+

heat

C

CH3CH(OH)(CH2)3CH2ClHot KMnO4(aq), H3O+NaOH(alcohol)

Heat

D

CH3

Hot KMnO4(aq), H3O+



The pinacol rearrangement involves the reaction of a diol in acidic conditions to form a carbonyl compound as shown below.

Which one of the following structural formulae is not a product of the pinacol rearrangement of 2,3-diphenylpentane-2,3-diol with the structure as shown below?

OH

OH

2,3-diphenylpentane-2,3-diol

A C

B D

O



Compound X is boiled under reflux with an excess of aqueous sodium hydroxide.

Compound X What is the main product?

A C

B D


An ester Y is boiled with aqueous hydrochloric acid and the resulting mixture is cooled. The final products include a compound C4H8O2 which gives a pale yellow precipitate with alkaline aqueous iodine. Which formula could represent Y?

A CH3OCOCH2CH2CH3

B C6H5CO2CH2CH2CH2CHO

C CH3CO2CH2CH2COCH3

D C6H5CO2CH(CH3)CH2CH2OH


Tyramine is an alkaloid found, among other places, in mistletoe and ripe cheese.

NH2

HO


Tyramine

How many moles of ethanoyl chloride react completely with one mole of tyramine?

A 0 B 1 C 2 D 3


Which sequence correctly shows the compounds, in aqueous solutions of equal concentration, in order of increasing pH?

A C2H5OH < C6H5COCl < CH3CH(NH2)CO2H < CH3CH2NH2

B CH3CH2OH < CH3CH2NH3+Cl

- < C6H5NH2 < CH3CH2NH2

C C6H5OH < C6H5NH2 < CH3CONH2 < CH3CH2NH3+Cl

-

D CH3COCl < C6H5CO2H < CH3CONH2 < C6H5NH2


A liquid P is sparingly soluble in water but dissolves readily in cold hydrochloric acid. Evaporation of this solution yields a crystalline solid. What is the identity of P? A C6H5NH2

B C6H5CH3

C CH3(CH2)10CONH2

D HO2CCH(CH3)NH2

YJC/PRELIM2009/P1/Q17





















MCQ – Section B ACJC/PRELIM 2009/P1/Q39 1 Which of the following reactions will give identical observation?

1 Bromine and ethene

2 Bromine and ethane in the presence of uv light

3 Bromine and benzene in the presence of halogen carrier

ACJC/PRELIM 2009/P1/Q40 2 Compound X has molecular formula C3H4O4.

It can react with HCl to give C3H3O3Cl.

One mole of X reacts with sodium metal to give one mole of H2 gas.

Which of the following can be X?

1 CH2(OH)COCOOH

2 CHOCH(OH)COOH

3 CH2(COOH)2

AJC/PRELIM 2009/P1/Q37 37 Dopamine is a neurotransmitter found in many animals, including vertebrates

and invertebrates. Which of the following statements are correct?

HO

HO

CH2CH

CO2H

NH2

dopamine

1 1 mole of dopamine reacts with 3 moles of acyl chloride

2 1 mole of dopamine reacts with 1 mole of HBr.

3 1 mole of dopamine reacts with 3 moles of Na2CO3



37 Ethyl propanoate, CH3CH2OCOCH2CH3 undergoes acidic hydrolysis in the presence of H2

18O. Which of the following products are formed? 1 CH3CH2

18OH

2 CH3CH2CO18OH

3 CH3CH2OH


38 Which of the following molecules are planar?

1 CHO

2

C

H

C

H

CNO2N

3


39 In which sequence are the compounds listed in order of increasing ease of hydrolysis?

1 C6H5Cl, CH3CH2Cl, CH3COCl

2 CH3CH2I, CH3CH2Br, CH3CH2Cl

3 C6H5Cl, CH3Cl, CH3CH2Cl


40 The molecule of benzene, C6H6 is a regular hexagon in which the electrons are

described as delocalised. Which of the following statements support this structure?

1 It prevents benzene from undergoing addition reactions.

2 All C–C bonds lengths in benzene are intermediate between C–C bond in an alkane and C=C bond in an alkene.


3 The enthalpy change of hydrogenation of benzene is less exothermic than that predicted for cyclohexatriene.


Step 1 Step 2

CJC/PRELIM 2009/P1/Q36 36

CH=CH2

CH3

CHBrCH3

CH3

COOH

COOH

COOH

COOHO2N

COOH

COOHNH2

step 1 step 2 step 3

step 4

Which type of reaction has taken place in the above reaction scheme?

1 electrophilic substitution

2 oxidation

3 reduction CJC/PRELIM 2009/P1/Q37 37 Chloroethane can be formed from bromoethane in two steps. CH3CH2Br CH3CH2OH CH3CH2Cl Which statements about these steps are correct?

1 Step 1 involves a nucleophilic substitution.

2 Hot aqueous sodium hydroxide is the reagent in step 1.

3 Hot aqueous sodium chloride is the reagent in step 2. CJC/PRELIM 2009/P1/Q38 38 Benzoylglycine (hippuric acid) was first isolated from stallions‟ urine. Which properties does this compound possess? 1 It can be hydrolysed to produce an amino acid.

2 It can be made by reacting benzoyl chloride, C6H5COCl with aminoethanoic acid, NH2CH2CO2H.

3 It can be neutralised by reaction with cold aqueous sodium hydroxide.

I II III

IV

CONHCH2CO2H


CJC/PRELIM 2009/P1/Q39 39 Which of the following compounds form a single organic product when it is

heated with acidified potassium manganate(VII) solution?

1 2 3

CH3–CH2–CH2–CH=CH2

CH3

CH3

CH3

CJC/PRELIM 2009/P1/Q40 40 For the upcoming inaugural Youth Olympics Games (YOG) in Singapore, former

Olympic winners will share their experiences with participating athletes in dealing with competition pressures and sport injuries.

One common sport injury is muscle sprain. To reduce swelling and pain,

ibuprofen is usually administered. The structure of ibuprofen is shown.

Which of the following are expected to be true for ibuprofen?

1 On heating with hot acidified KMnO4, the following is formed:

2 It has very low solubility in water.

3 It can be reduced by LiAlH4.

CO2H

CH3

CH3

H3C

CO2H

HO2C

CH3



37. Alkanes can be prepared from iodoalkanes by heating under reflux with sodium (in ether) according to the equation:

2RI + 2Na → R–R + 2NaI

Which alkanes will be produced if a mixture containing equal amounts of CH3CH2I (iodoethane) and CH3CHICH3 (2-iodopropane) is used?

1

CH3−CH−CH−CH3

2

CH3−CH2−CH−CH3

3 CH3−CH2−CH2−CH3


38.

HCCH2CH2CH2CH2CCH2CH3

Based on the information given in the reaction scheme above, which of the following

CH3

CH3

CH3

O 1. CH3CH2MgBr, ether 2. H3O

+ OH

CH2CH3

Conc. H2SO4, heat

CH2CH3

1. O3 2. Zn, CH3COOH

O O


reaction is involved?

1 nucleophilic addition

2 dehydration

3 oxidation


39. Serine is an amino acid commonly found in human body. Its structural formula is CH2OHCH(NH2)CO2H.

Which of the following statements about serine are correct?

1 In a buffer solution of pH 9, serine is attracted towards the anode when a potential difference is applied.

2 In a polypeptide, the hydroxyl group of serine maintains the secondary structure by forming hydrogen bonds with polar R groups of other amino acid residues.

3

The zwitterionic form of serine is H3N−C−COO−


H

CH2O−

+


40. Which statements about methylamine, dimethylamine and trimethylamine are incorrect?

Compound pKb

CH3NH2 3.36

(CH3)2NH 3.29

(CH3)3N 4.28

1 They are trigonal planar with respect to the nitrogen atom.

2 They all form amides with ethanoyl chloride.

3 Trimethylamine is a weaker base than dimethylamine due to the steric hindrance which decreases the chances of protonation.


36

Consider the following reaction scheme involving benzaldehyde and ammonia in methanol to form an imine.

CHO

+ NH3

NH

+ H2O

Which of the following statement(s) is/are true?

1 Ammonia is the nucleophile in this reaction.

2 The rate of backward reaction is increased by the addition of H2O.

3 The yield of imine is increased by the addition of NaOH to the

reacting mixture of benzaldehyde and ammonia. DHS/PRELIM 2009/P1/Q37

37

When iodoethane is heated to about 100C in a sealed tube with concentrated ammonia solution, the possible product(s) is/are

1 C2H5NH2


2 (C2H5)2NH

3 (C2H5)3N


38

The compound below is Binapacryl which is often used as a fungicide.

OH

O2N

NO2

CH3

CH3

Which of the following statement(s) is/are true about the fungicide?

1 It undergoes a more vigorous reaction with potassium metal than

sodium metal.

2 It reacts with ethanoic acid in the presence of concentrated sulfuric acid to give a pleasant smelling liquid.

3 It cannot exist as a racemic mixture . DHS/PRELIM 2009/P1/Q39

39

Vitamin B5 has the following structure.

NH O

CH3 CH3

OH

OH

O OH

Which of the following statement(s) correctly describe the chemistry of Vitamin B5?

1 Vitamin B5 reacts with 3 moles of PCl5.

2 The carboxylic acid group reacts with CH3NH2 to form an amide.

3 Vitamin B5 reacts with 2 moles of HCN.


40

Psilocin is a psychedelic mushroom alkaloid. It is the active compound that produces hallucinations from ingesting “magic mushrooms” and amplifies sensory experience. Compound Y is a derivative of Psilocin.


OH

NH

NH

CH3

Y

Which of the following statement(s) is/are true about Y?

1 It gives white fumes with CH3COCl.

2 It dissolves in both aqueous acids and alkalis.

3 The nitrogen-containing group in the ring has a lower pKb than the

nitrogen-containing group in the side chain.


37 In which of the following reactions is the reactive carbon tetrahedral in the organic

intermediate?

1 CH4 + Cl2uv

CH3Cl + HCl

2 HCHO + HCNtrace KCN

CH2(OH)CN

3 AlCl3

+ HClCl+ Cl2


38 Which statements about the complete combustion of an alkene, CnH2n, in oxygen are

correct?

1 The volume of oxygen required is directly proportional to the number of carbon

atoms present in the molecule.

2 The volume of gas produced at 25 C is the same as for the complete

combustion of an alkane with the same number of carbon atoms per molecule.

3 At 120 C, the volume of steam produced is always twice the volume of carbon

dioxide.



39 Compound F is used to treat urinary incontinence. The structure of F is shown below.

NH

HO

OH

CH3

OOH

O

H3C CH3

F

Which of the following statements about the reactions of F are incorrect?

1 1 mol of F reacts with SOCl2 to release 3 mol of HCl gas.

2 1 mol of F reacts with Na metal to release 3 mol of H2 gas.

3 1 mol of F reacts with Na2CO3 to release 2 mol of CO2 gas.


40 Which sequence shows the nitrogen compounds in increasing order of pKb value?

1 CH3CH2NHCH3, C6H5CH2NH2, CH3CONH2

2 C6H5NH2, NH3, CH3NH2

3 CH3CH2N(CH3)2, C6H5NH2, CH3CH2NHCH3

MI/PRELIM 2009/P1/Q37 Reactants that form an organic product which has an asymmetric carbon atom include 1 but-2-ene and HBr 2 propanal and HCN 3 propanone and NaBH4 MI/PRELIM 2009/P1/Q38 A car burning lead-free fuel has a catalytic converter fitted to its exhaust. On analysis, its exhaust gases are shown to contain small quantities of nitrogen oxides. Which modifications would result in lower exhaust concentrations of nitrogen oxides? 1 an increase in the surface area of the catalyst in the converter. 2 an increase in the rate of flow of the exhaust gases through the converter. 3 a much higher temperature of combustion in the engine. MI/PRELIM 2009/P1/Q39 The drug tamoxifen, which is used in the treatment of cancer, has the structure


Which of the following statement(s) about tamoxifen is/are correct?

1 it is insoluble in HCl(aq). 2 it has a stereoisomer. 3 it can undergo free radical substitution with chlorine. MI/PRELIM 2009/P1/Q40 Which of the following correctly list(s) the compounds in order of decreasing acidity? 1

OH

CH3

OH OH OH

Cl

, , ,

OH

NO2

OH OH OH

CH3

, , ,


2 3


Samples of the gases CH3Cl and Cl2 are mixed together and irradiated with light. Which statements are true? 1 Chlorine atoms are formed in the initiation step.

2 The chlorine radical acts as a catalyst in the propagation steps.

3 Ethane is produced in trace amounts in the termination step.


Which reagents can be used to distinguish between these two compounds?

C CHO

H

CH3H

O

C CH

CH3

CH2Br

O

CHO 1 Fehling‟s solution

2 Silver nitrate solution

OH

CONH2

OH

CH2OH

, , ,

NH2


3 Alkaline iodine solution


Which reactions yield a carbon compound incorporating deuterium, D? [D =2H] 1 CH3COCH3

2 CH3CO2CH3

3 CH3CH2CN


Nylon is a biodegradable polymer used in clothes manufacturing. A section of the nylon molecule shown below: ( NH(CH2)5CO )n

Which statement about nylon is true? 1 It contains amide linkages.

2 It is basic.

3 It gives an orange precipitate with 2,4-dinitrophenylhydrazine.


Pentaerythritol is an intermediate in the manufacture of paint.

C

CH2CH2

CH2 CH2

OH

OHOH

OH

pentaerythritol

Which of the following statements about pentaerythritol are correct? 1 It decolourises acidified potassium manganate(VII) on warming

NaOD, I2

D2O

NaOD

D2O

NaOD

D2O


2 It reacts with metallic sodium

3 It is formed via the reaction of 1,4-pentadiene,

CH2 CH CH2 CH CH2 with cold dilute potassium manganate (VII)


Which of the following statements is true of the nitration of benzene?

1 Concentrated H2SO4 acts as an acid to generate the NO2+ ion

2 Concentrated H2SO4 acts as a catalyst

3 The organic intermediate has five carbon atoms which are sp

2

hybridised


Which of the following statement(s) is/are true for both methylbenzene and phenol? 1 Both can react with nitric acid via the same mechanism

2 Both reacts with aqueous bromine at room temperature to form at white precipitate

3 Both reacts with hot acidified KMnO4 to form the same organic product


Capsaicin, the active component of chilli peppers, has the following structure:

OH

OCH

3 N

H

O

CH3

CH3

capsaicin

Which of the following statements about capsaicin are correct?


1 It contains a total of nine sp2 hybridised carbon atoms

2 It reacts with dilute hydrochloric acid under room temperature

3 It has only one chiral centre














Thyroxine and Cyproterone are compounds that are often used in hormone therapy.

HO

I

I O

I

I

CH2 C

H

NH2

COOH

Thyroxine

O

Cl

COCH3

OHCH3

CH3

Cyproterone

Which of the following reagents could be used to distinguish between the two

compounds?

1 Neutral FeCl3

2 Alkaline aqueous iodine

3 Sodium carbonate


Which of the following properties of benzene may be directly attributed to the stability

associated with the delocalised electrons?

1 Its susceptibility to attack by nucleophilic reagents.

2 Its tendency to undergo substitution rather than addition reactions.

3 The carbon-carbon bond lengths are between those of C-C bonds and C=C

bonds.


By varying the conditions of the reaction between propan-1-ol and concentrated sulfuric

acid, which of the following compounds can be obtained?

1 CH3CH=CH2

2 CH3CH2CH2OCH2CH2CH3

3 CH3CH2CH2OSO3H



Compound Q, with molecular formula C6H12, was reacted with acidified potassium

manganate(VII) and the resultant mixture obtained was colourless. The mixture was

thereafter distilled to form distillate R and residual solution S.

Distillate R is able to form a yellow precipitate with alkaline aqueous iodine.

Residual solution S reacts with sodium carbonate to form a colourless gas.

Which of the following statements are true?

1 Compound Q will decolourise aqueous bromine

2 Distillate R can form an orange precipitate with 2,4-dinitrophenylhydrazine

3 Residual solution S can form white fumes with PCl5.




Which of the following compound(s) forms a yellow precipitate when warmed with alkaline aqueous iodine?

1 butan-2-ol

2 1-phenylethanol

3 2-phenylethanol

Which of the following reagents can be used to distinguish between C6H5CHO and C6H5COCH3?

1 Aqueous [Ag(NH3)2]+

2 Alkaline solution of iodine

3 2,4-dinitrophenylhydrazine

It has been noted that prolonged exposure of wine to the atmosphere will result in the wine becoming “vinegary”. Therefore, wineries attempt to prevent such exposure by storing the wine in a mixture of carbon dioxide and nitrogen. How does this mixture prevent the “vinegary” taste from occurring?

1 Oxidation of ethanol into ethanoic acid will be prevented.

2 The acidity of the wine will be decreased.

3 The amount of carbon dioxide dissolved in the wine will be increased.




Psilocin is a psychedelic mushroom alkaloid which is the active compound that produces hallucinations from ingesting “magic mushrooms” and amplifies sensory experience. Compound K is a derivative of Psilocin.

OH

N

H

CH2 CH2 N

H

CH3

Compound K Which of the following statement(s) is/are true for compound K?

1 It gives white fumes with CH3COCl.

2 It dissolves in both aqueous acids and alkalis.

3

The nitrogen containing group in the ring has a lower pKb than the

nitrogen containing group in the side chain.







Compound X changes the colour of excess hot acidified potassium dichromate(VI) from orange to green. Which of the following can be compound X?

1 C6H5CH2CHO

2 C6H5CH(OH)CH3

3 C6H5CO2CH2CH3


The cholesterol-lowering agents called statins, such as pravastatin, are among the most widely prescribed drugs in the world.


Which statements about pravastatin are correct?

1 The pravastatin molecule has 8 chiral centres.

2 When treated with an excess of hot concentrated acidified KMnO4, pravastatin will produce a compound with which gives an orange precipitate with 2,4-dinitrophenylhydrazine.

3 When 1 mole of pravastatin is treated with an excess of sodium, 2 moles of hydrogen is produced.


GABA is a neurotransmitter released by red algae which encourages shellfish larvae to settle on the ocean bed.

H2NCH2CH2CH2CO2H

GABA

Which statements about GABA are correct?

1 It is a 2-aminocarboxylic acid.

2 It is soluble in water due to zwitterion formation.

3 It migrates to the anode of an electrolytic cell at pH 12.








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