chapter 16-20 chempro question.pdf

[CHEM PRO SEMESTER 2] 2013/2014

CHAPTER 16: CARBONYL COMPOUNDS

SESSION : 2005/2006

1. The structure of A is given below:

i. Name the functional group present in A.

ii. Is A optically active? Explain.

iii. Draw a pair of enantiomers of A.

[4 MARKS]

2. (a) Write structural formula for the products formed when propanal is treated with

reagents of lithium aluminium hydride followed by hydrolysis; phenylmagnesium

bromide followed by hydrolysis; hydroxylamine; and sodium bisulphate respectively.

[4 MARKS]

(b) Compound with molecular formula C9H10O is a monosubstituted benzene. It forms a

yellow precipitate when treated with 2,4-dinitrophenylhydrazine, but does not

decolorize bromine in carbon tetroxide. Draw all the possible isomeric structural

formula for the compounds. Explain.

State the observations on how the isomeric compounds can be differentiated using

Tollens reagent and iodoform test. Write the reaction equations involved.

[11 MARKS]

H3C C

O

CH

CH3

C

CH3

CH3

CH3

Structure A


SESSION : 2006/2007

1. Compound B, C4H10O can exist in many isomeric alcohols.

i. Draw all isomers of the alcohol.

ii. State the isomers that can be prepared by reduction of carbonyl compounds.

[7 MARKS]

2. Compound S, C7H6O gives a yellow precipitate with 2,4-dinitrophenylhydrazine.

Catalytic hydrogenation of S yields T, C7H8O. Oxidation of T gives benzoic acid and

nitration of benzoic acid forms U. Determine the structures of S, T and U. Write all the

chemical equations involved in the above reactions.

[10 MARKS]

SESSION : 2007/2008

1. An aldehyde, EE reacts with ethylmagnesium bromide followed by acid hydrolysis forms

compound FF, C6H14O. Treatment of FF with concentrated sulphuric acid gives GG,

C6H12. Reaction of GG with ozone followed by zinc in water yields two products,

propanal and propanone.

Identify compound EE through GG. Write an equation for each chemical equation

reaction involved.

Suggest another Grignard reagent and carbonyl compound which can be used to prepare

compound FF.

[8 MARKS]


SESSION : 2008/2009

1. Compound P has a molecular formula of C7H15Br. Treatment of P with sodium ethoxide

in ethanol yields three isomers Q, R and S. Hydrogenation of Q, R and S forms only 3-

methylhexane. Reactions of Q, R and S with hydrogen bromide in the presence of

hydrogen peroxide gives three isomers T, U and V respectively, with the same molecular

formula as P. Ozonolysis of Q gives a mixture of W and X. Both W and X give negative

result with iodoform test.

Draw the structures P through X and explain your answer. Write the reaction equation

involving the ozonolysis of Q.

[15 MARKS]

SESSION : 2009/2010

1. 2,2,4-trimethylpentane, Q, is used as an antiknock agent in the combustion technology.

Monobromination of Q gives R as a major product. R undergoes dehydrohalogenation to

form S and T. Oxidative cleavage of S gives two products, U, a ketone and V, a

carboxylic acid.

Write chemical equations for the complete and incomplete combustions of Q,

monobromination of Q and oxidation of S. Explain the formation of R in terms of radical

stability. Suggest the structures of S, T, U and V.

By using two-step reaction, show how U can be prepared from an alkene of your choice.

[15 MARKS]

2. Show how you would convert 3-cyclopentylbutanal to an amide.

Describe how Fehlings test can be used to detect the presence of a carbonyl group in

3-cyclopentylbutanal.

[9 MARKS]


SESSION : 2010/2011

1. Dehydration of alcohol G gives compounds H and J. Draw the structures of H and J.

Determine the major product and show the mechanism for its formation.

When G reacts with PCC,compound K is formed. Draw the structure of K. Give the

reagent used to test the presence of K and write the chemical reaction.

[10 MARKS]

2. Two compounds A and B were formed when compound X (C7H14) was reacted with

ozone followed by treatment with Zn/H2O. Both A and B reacted with 2,4-

dinitrophenylhydrazine. Compound B gave positive iodoform test, which on acidification

yielded propanoic acid, and negative Fehlings test, whereas A gave negative iodoform

test and positive Fehlings test. Deduce the structures of X, A and B. Write the complete

equations for all the reactions involved.

[11 MARKS]

SESSION : 2011/2012

1. 2-methylpentane reacts with Br2 in the presence of light to yield L, a monobromination

product. Dehydrohalogenation of compound L forms M and N as the respective major

and minor products. Oxidative cleavage on M gives ketone P and carboxylic acid Q;

whereas similar reaction on N forms ketone R and CO2. Treatment of M with acidified

water yields S.

Write the chemical equations for complete combustion of 2-methylpentane;

dehydrohalogenation of L; and oxidative cleavage of M. Suggest the structures of L, M,

N, P, Q, R and S. Write the mechanism for the formation of S.

Show how Q can be synthesized from ethane.

CH2CH2OH

G


[20 MARKS]

SESSION : 2012/2013

1. Reaction of compound I are shown in the following scheme.

CH2 C CH3

O i. NaBH4

ii . H3O+

J

I

NaHSO3

K

(i) Draw the structure for J and K.

(ii) What is the nucleophile involved in the formation of J ?

(iii) Suggest a chemical test to differentiate between I and J. State the observation and

write the chemical equation involved.

(iv) Show how I can be synthesized from an alkyl halide containing nine carbon

atoms.

[10 MARKS]


CHAPTER 17 : CARBOXYLIC ACIDS

SESSION : 2005/2006

1. Arrange the following compounds in order of increasing acidity. Explain.

Ethanoic acid phenol 2-chloroethanoic acid ethanol

I II III IV [4 MARKS]

SESSION : 2006/2007

1. Based on the following reaction scheme, draw the structure of F, G, H and J.

C

O

OHCH

3CH(OH)CH

3 / H+

SOCl2

CH3CH

2NH

2

J

G

H

F

i. LiAlH

ii.H+

[4 MARKS]

2. Compound K, C5H10 reacts with bromine in the presence of ultraviolet light to give only L,

C5H9Br. Compound K does not react with acidified solution of potassium manganate (VII).

Upon treatment with potassium t-butoxide, L gives only one product, M, C5H8. M

decolourises bromine water and ozonolysis of M gives N, C5H8O2.

Deduce the structures of compounds K through N. write an equation for the reaction of M with

bromine water.

[8 MARKS]


3. Compound S, C7H6O give a yellow precipitate with 2,4-dinitrophenylhydrazine. Catalytic

hydrogenation of S yields T, C7H8O. Oxidation of T gives benzoic acid and nitration of

benzoic acid forms U.

Determine the structures of S, T and U. Write all the chemical equations involved in the above

reactions.

[10 MARKS]

4.

(a) Ozonolysis of compound X produces Y, C6H10O and methanal. Treatment of Y with KCN,

followed by acidification yields Z. Hydrolysis of Z gives compound AA of which structure of

AA is shown below. Dehydration of AA yields BB. Deduce the structures of X, Y, Z and BB.

AA

Suggest one chemical test to differentiate Y from methanal. State the observation and write

the chemical equations.

[7 MARKS]

(b) Suggest two synthetic routes for the preparation of pentanoic acid from 1-chlorobutane.

[8 MARKS]

OH COOH


SESSION : 2007/2008

1. Explain the following statements.

i. 4-chlorobutanoic acid is less acidic compared to 2-chlorobutanoic acid

ii. pKa value of 4-nitrobenzoic acid is 3.41 whereas the pKa value of benzoic acid

is 4.19 [5 MARKS]

2. Compound X, C7H14 is optically active. On catalytic reduction of X over palladium, one

mole equivalent of hydrogen was absorbed yielding compound Y, C7H16. Reaction of X with

hot acidified solution of potassium permanganate gives ethanoic acid and compound Z,

C5H10O2 which is an optically active carboxylic acid.

Draw the structures for X, Y and Z. Explain your answer. Give the IUPAC name of X.

Propose a mechanism for the reaction of X with HCL that leads to the formation of the major

product.

Suggest a chemical test to distinguish compound X from Y. State the observation and write the

chemical equations. [15 MARKS]

3.Benzaldehyde is an aromatic aldehyde which can be found in bitter almonds. Show how

benzaldehyde can be synthesized from benzene.

[8 MARKS]

4. Alkaline hydrolysis of compound HH, C7H14O2 gives compounds JJ and KK. Treatment of

JJ with HCl yields carboxylic acid LL, C3H6O2. Compound KK gives a positive iodoform

test. When KK is treated with Lucas reagent, a cloudy solution forms after 10 minutes.

Explain the observation and propose the structures of HH, JJ KK and LL.

[7 MARKS]


SESSION : 2008/2009

1.Based on the following reaction scheme, draw the structures of G, J and K and give reagents F

and L.

CH3CH2CH2BrF

CH3CH2CH2CN

H3O+

GL

J

J

K

SOCl2CH3CH2CH2CONH2

[5 MARKS]

2. Propose a synthetic route for the preparation of cyclopentanecarboxylic acid from

cyclopentane via Grignard reagent. Cyclopentanecarboxylic acid reacts with ammonia to form

Y, and upon heating, Y yields Z. Draw the structures of Y and Z.

[8 MARKS]

3. Reduction of compound AA, C7H12O gives BB. Dehydration of BB yields CC, and ozonolysis

of CC forms OHCCH2CH2CH(CH3)CH2CHO. Compound DD obtained when AA reacts with

HCN. Acid hydrolysis of DD gives EE.

Determines the structures of AA, BB, CC, DD and EE. Write all the reaction equations

involved.

[10 MARKS]


CH3CH2CH(OH)CH3 CH3CH2C(CN)(OH)CH3CH3CH2CCH3

O

E F

CH3CH2C(COOH)(OH)CH3

CH3CH2CO- + CHI3

O

HG

ICH3CH2COH

O

K L

MN

CH3COOH

SOCl2 CH3CH2OH/ H+

Ca CH3CH2NH2

SESSION : 2009/2010

1.

(a) Based on the reaction scheme below, suggest reagent E to I.

[5 MARKS]

(b)

(i) Draw the structure the products K through N in the following reaction scheme.

(ii) Give IUPAC name for the carboxylic acid in the above reaction scheme.

[5 MARKS]


2.

2,2,4-trimethylpentane, Q is used as an antiknock agent in the combustion technology.

Monobromination of Q gives R as a major product. R undergoes dehydrohalogenation to

form S and T. Oxidative cleavage of S gives two products, U, a ketone and V, a carboxylic

acid.

Write chemical equations for the complete and incomplete combustions of Q,

monobromination of Q and oxidation of S. Explain the formation of R in terms of radical

stability. Suggest the structures of S, T, U and V.

By using a two-step reaction, show how U can be prepared from an alkene of your choice.

[15 MARKS]

3.(a) Show how you would convert 3-cyclopentylbutanal to an amide.

Describe how Fehlings test can be used to detect the presence of a carbonyl group in

3-cyclopentylbutanal.

[9 MARKS]

(b) Match the pKa values in the table with the following compounds:

Phenol, ethanoic acid and ethanol

pKa 4.76 9.89 16

Compound

Explain your answer in terms of their conjugate bases.

[6 MARKS]


SESSION : 2010/2011

1.

(a) TABLE 2 shows the boiling points and solubilities of pentane, 1-butanol, methyl ethanoate

and propanoic acid.

TABLE 2

Compound Molecular

mass

Boiling point, oC Solubility in water,

g/100g

Pentane 72 36 0.04

1-butanol 74 117 8.3

Methyl ethanoate 74 57 24.4

Propanoic acid 74 141

(i) Explain why propanoic acid has the highest boiling point and most soluble?

(ii) Explain why the boiling point of 1-butanol is higher than that of methyl ethanoate

whereas the solubility is the reverse?

[5 MARKS]

2. Arrange acetic acid, ethanol and phenol in order of increasing acidity. Explain in terms of the

stability of their conjugate bases.

[4 MARKS]


SESSION : 2011/2012

1.

(a) Treatment of 1-bromobutane with sodium cyanide gives I. Hydrolysis of I forms J.

(i) Draw the structures of I and J. (ii) Give IUPAC name of compound J.

[3 MARKS]

(b) Suggest the products formed when J reacts with

(i) methanamine with heating. (ii) LiAlH4 followed by hydrolysis. (iii) SOCl2. (iv) Ethanoic acid.

[4 MARKS]

(c) Indicate the reagents needed for the following conversions:

(i) butanone to 2-butanol. (ii) butanone to 2-hydroxy-2-cyanobutane. (iii) benzene to acetophenone.

[3 MARKS]

(d) Arrange the following compounds in descending order of acidity. Explain your answer.

Phenol, cyclohexanol, benzoic acid, 4-nitrophenol

[5 MARKS]

2. Compound T is formed from the reaction of benzene with chloroethane in the presence of

AlCl3. Chlorination of T in light gives monochlorinared compounds U (major product) and V.

Treatment of T in acidified solution of KMnO4 produces W. Hydrolysis of U froms X; whereas

reaction of U with nucloephile Z produces Y, C6H5CH(OCH2CH3)CH3. Reagent AA transforms

X to acetophenone while reagent BB converts the acetophenone to carboxylic acid.

Draw the structures of compounds T, U, V, W and X and state the reagents AA and BB. Name

the reaction for the formation of T and write the mechanism. State whether the hydrolysis of U

occurs via SN1 or SN2 mechanism and show the mechanism chosen. Give the nucleophile Z.

Compound Y is optically active. Draw a three-dimensional structural formula for an

enantiomeric pair of Y.

[20 MARKS]


SESSION : 2012/2013

1. Arrange the following compounds in ascending order of acidity. Explain your answer.

2,3-dichlorobutanoic acid, 1-butanol, butanoic acid, 4-chlorobutanoic acid,

2-chlorobutanoic acid.

[5 MARKS]


Chapter 18 Amines

PSPM 2005/2006

1. Write the reaction to produce iodobenzene, from benzene via diazonium salt.

[4M]

PSPM 2006/2007

2. Arrange the following compounds in ascending order of boiling points. Explain your

answer.

N,N- dimethylmethanamine, 1-propanamine, n-butane, 1-propanol

[5M]

3. Amphetamine is one of the organic compounds used in medicine. The structure of

amphetamine is as shown below.

Show how Hinsbergs test is used to identify the presence of amino group in

amphetamine. State the observations and write all the reaction equations.

[5M]


PSPM 2007/2008

4. Based on the reaction scheme below, draw the structures of J, K, L, M and N.

[5M]

5. The sctructure of 4-hydroxyazobenzene is as shown.

Suggest how the above compound can be synthesised using benzene and phenol.

[7M]


PSPM 2008/2009

6. Based on the reaction scheme below, draw the structures of M and N. State the reagent

used in the Hofmann degradation reaction.

Suggest a chemical test to differentiate M from N. State the observations and write all the

reaction equations involved.

[ 5M ]

7. Compounds GG, HH and JJ are isomers with a molecualr formula of C4H11N. JJ is

formed from the reaction of 1-chloropropane with sodium cynaide, treatment with

LiAlH4 and followed by hydrolysis. GG reacts with an alkaline solution of

benzenesulphonyl chloride to form a precipitate, KK which does not dissolve on

acidification. When HH is added to alkaline solution of benzenesulphonyl chloride, two

layers are form which dissolve upon acidification. Deduce the structural formulae of GG,

HH and KK. Give your reason. [7M]

PSPM 2009/2010

8. Arrange basicity methanamine, ammonia and N-methylmethanamine in descending order

of basicity. Explain your answer. Show how you would differentiate methanamine from

N-methylmethanamine.

[7M]

PSPM 2010/2011

9. Write an equation for the formation of nitrous acid (HNO2). Show how cyclohexanamine

and piperidine can be differentiated using this acid.

M Hofmann degradation CH3CH2CH2NH2

N

i. LiAlH4

ii. H+


[5M]

10. Give the reagents A and D and the intermediates B and C in the following reaction

scheme. The final product reacts with benznesulphonyl chloride in excess potassium

hydroxide followed by acidification. Give the observations and write the reaction

equations involved.

[6M]

PSPM 2011/2012

11. Draw the structural formula of the aromatic amines with a molecular formula C7H9N.

Classify them into primary and secondary amines. Suggest a chemical test to differentiate

between a chosen primary and the secondary amines. State the observation and write the

chemical equations involved.

[10M]


PSPM 2012/2013

12. Draw the structure of the products B through F in the reaction below.

[5M]

13. Arrange the following amines in ascending order of basicity. Explain your answer.

Aniline, propylamine, N-methylethanamine, N, N-dimethylethanamine

Indicate an amine that can be prepared through Hoffmanns degradation.

Write the chemical equation for this reaction.

Suggest a chemical test to differentiate between propylamine and N-methylethanamine.

State the observation and write the chemical equation involved.

[10M]


Chapter 19 Amino Acid

PSPM 2005/2006

1. Threonine is a naturally occurring amino acid.

Threonine

Give the IUPAC name for threonine and draw the structure of its zwitterions. Draw the

structures of the products formed when threonine is dissolved separately in acidic and

basic solutions. Give the product if threonine is reacted with NaOH. Draw the dipeptide

structure of threonine. [6M]

PSPM 2006/2007

2. Serine and alanine are examples of -amino acids.

Give the IUPAC name of serine. Draw the structures of serine each in a strongly acidic

and basic medium. Draw the structures of all possible dipeptides when serine is reacted

with alanine.

[5M]

H2N

H

COOH C

C

CH3

HO H


PSPM 2007/2008

3. The IUPAC name of alanine is 2-aminopropanoic acid. Two moles of alanine undergo

condensation reaction to form dipeptide QQ. Alanine reacts with sodium nitrite in

hydrochloric acid at 0C and left at room temperature to form RR, SS and TT. Draw the

structures of QQ, RR , SS and TT.

[ 4M ]

PSPM 2008/2009

4. Serine, with an isoelectric point of 5.7 has the following structure :

What is meant by an isoelectric point? Draw the structures of serine at pH 3, pH 10 and at

its isoelectric point.

[ 4M ]

PSPM 2009/2010

5. Draw all the dipeptides that can be formed from compounds DD and EE. Draw the

zwitterions of DD.

[ 3M ]

HO OH

O

NH2

CH3CH2CHCHCOOH

NH2

CH3

CH3CHCHCOOH

NH2

CH3

DD EE


PSPM 2010/2011

6. The structure of aspartic acid is as follows :

Give its IUPAC name. Draw the structure of the products when aspartic acid is reacted

with methanol in the presence of concentrated H2SO4, and when aspartic acid reacts with

another molecule of aspartic acid. What is the net charge of aspartic acid in a basic

medium? [ 5 M ]

PSPM 2011/2012

7. The structure of amino acid CC is as shown below:

CC

Compound CC reacts with dilute mineral acid to form DD, whereas EE is formed when

CC is treated with nitrous acid. Condensation two moles of CC forms a dipeptide FF.

Give IUPAC name for CC and draw the structure of its zwitterion. Draw the structures of

DD, EE and FF. Show the peptide bond in FF.

[6M]

CH2CHCOOH

NH2

CCH2CHC HO HO

O O

NH2


PSPM 2012/2013

8. Amino acids are molecules containing an amino group ,a carboxyl group and various side

chains.

Amino acids are linked together to form proteins .Name the bond linking the amino acids .

Two molecules of glutamic acid react to form a dipeptide .Draw the structure of the dipeptide

.Based on the structure below ,is glutamic acid acidic or basic ? Explain by drawing the

structure of zwitterion .

[5M]


Chapter 20 Polymer

PSPM (05/06)

1) What is meant by addition polymerisation and condensation polymerisation? Draw the polymer formed using the following monomer:

State the type of polymerisation based on its information.

[5M ]

PSPM (06/07)

2) Polymer PP , shown below is prepared by condensation polymerisation.

PP

Define condensation polymerisation. Name the polymer PP and draw the structures of its

monomer. State the type of linkage shown by the arrow.

[5M]

PSPM (07/08)

3) The structure of polyetheneterepthalate(PET) is as shown.

Draw the structures for the monomers, name the polymerisation process and state one of its uses.

[4M]

CHCICH2

N

H

N

H

C

O

C

O

C

O

C

O

OCH2CH2O

Polyetheneterepthalate(PET)

n

n


PSPM (08/09)

4) The structure of monomers PP and QQ are as shown.

Draw all possible structures of homopolymer and copolymer which can be formed from

monomers PP and QQ.

[4M]

PSPM (09/10)

5) Draw the structure of monomer for polypropylene. Name the type of polymerisation that produces polypropylene. Show how polypropylene can be prepared from its monomers. Give

2 uses of polypropylene.

[5M]

PSPM (10/11)

6) Give the monomers for the following polymer and state the type of polymerisation.

Classify this polymer according to its linkage groups.

[4M]

C C OCH2CH2O

O O

n

Polyetheneterepthalate (PET)

CHCIH2CPP

CH3CH CF2QQ


PSPM (11/12)

7) Terylene has the repeating unit as shown below. Give the structural formula of the monomers and name the polymerization process for the formation of terylene. Give one usage of

terylene.

[4M]

PSPM (12/13)

8) Lexan polycarbonate is formed from the reaction of X and Y. One mole of X reacts with

one mole of Y to release two moles of HCl.

Draw the structures of X and Y. Name the type of this polymerization. State one usage of this

polymer. Suggest a compound that can replace one of the monomers.

[5M]

C C OCH2CH2O

O O

n

Polyetheneterepthalate (PET)

chapter 16-20 chempro question.pdf

Documents

compound s

isomers q

marks session

marks b compound

structures of s

compound p

hydrogenation of q

ozonolysis of q