PRACTICE MODUL SK025 2nd Edition

PRACTICE MODULE CHAPTER 9 SK025

WORKSHEET 9.8

197

PRACTICE MODULE CHAPTER 9 SK025
198

PRACTICE MODULE CHAPTER 9 SK025

WORKSHEET 9.9

MODEL OF PSPM QUESTIONS

1. Two different compounds P and Q with molecular formula C5H10O have the same
skeletal structure. Compounds P and Q react with 2,4-DNPH to give orange precipitates
but there are no observable changes when reacted with I2/NaOH.

a) Draw the possible structures of P and Q.
b) Give the IUPAC names of P and Q.
c) Suggest a chemical test to distinguish between P and Q and write the chemical

equations.
[ 7 marks ]

2. Ozonolysis of compound G gives compounds H and J.

O O
CH
C
CH3

HJ

a) State the reagents used in the ozonolysis reaction.

b) By using a suitable explanation, propose the structure of G.

C Draw the structures of the intermediates and final products formed when H and
J react with ( 3)2CHMgBr, followed by hydrolysis.
Explain why H reacts with an alkaline solution of iodine whereas J does not.

d)

Prepared by : Mdm Melani Sari bt Wan Ismail
Checked by : Mdm Suhaibah bt Mustafa

199

PRACTICE MODULE CHAPTER 10 SK 025
MAPPING OF PHYSICAL PROPERTIES FOR CARBOXYLIC ACID

200

PRACTICE MODULE CHAPTER 10 SK 025

MAPPING OF CHEMICAL PROPERTIES FOR CARBOXYLIC ACID AND ITS
DERIVATIVES

REACTION OF CARBOXYL COMPOUNDS

NH3 excess H3O+ i)CO2 Na @K
 ii)H3O+

CH3CH2OH,H+ O Mg@Ca
 CH3 CH2 CH2 COH
NaOH
SOCl2 i) LiAlH4
pyridine ii) H3O+ NaHCO3
@Na2CO3
CH3COCl
pyridine

O OH KMnO4, H+
HC 

[Ag(NH )2 ] +,
3

OH -

201

PRACTICE MODULE CHAPTER 10 SK 025
CHAPTER 10 : CARBOXYLIC ACIDS & ITS DERIVATIVES

10.1 INTRODUCTION
WORKSHEET 10.1
1. Give the general formula of carboxylic acids
Ans:
2. Give the IUPAC name for the following compounds:
(a)
(b)
(c)

(d)

202

PRACTICE MODULE CHAPTER 10 SK 025
3. Give the IUPAC names for the following carboxylic acids:

4. Draw the structural formula corresponding to each name.
(a) 2–bromobutanoic acid
(b) 2,3–dimethylpentanoic acid
(c) 3,3,4–trimethylheptanoic acid
(d) 2–sec–butyl–4,4–diethylnonanoic acid
(e) 3,4–diethylcyclohexanecarboxylic acid
(f) 1–isopropylcyclobutanecarboxylic acid
(g) 3,3–dimethylpentanoic acid
(h) 4–chloro–3–phenylheptanoic acid
(i) o–chlorobenzoic acid
(j) 4–aminopentanoic acid
203

PRACTICE MODULE CHAPTER 10 SK 025

Answer :

204

PRACTICE MODULE CHAPTER 10 SK 025
10.2 PHYSICAL PROPERTIES
WORKSHEET 10.2
1. Draw the cyclic dimer structure formed between two molecules of propanoic acid.
Ans:

2. What is the main reason carboxylic acid has the highest boiling point as compared to
other compounds with comparable mass?

Ans:
3. Arrange the compounds in each set in order of increasing boiling point. Explain your

answer.
(a) methanoic acid, propanoic acid, butanoic acid, ethanoic acid
(b) C3H7OH, CH3COOH,HCOOCH3,C4H10
Ans:

205

PRACTICE MODULE CHAPTER 10 SK 025
4. Which following compound is more soluble in water?Explain

(a) Propanoic acid and heptanoic acid.
(b) Ethanoic acid and ethanedioic acid
(c) Ethanol, ethanoic acid and chloroethane.
Ans:

5. Arrange the following acids acccording to increasing acidity. Explain.
(a) C6H6OH, CH3OH,ClCH3COOH,C6H5COOH
(b) CH3COOH, CH2(Cl)COOH, CH(F2)COOH

Answer:

206

PRACTICE MODULE CHAPTER 10 SK 025

10.3 PREPARATION
WORKSHEET 10.3
1. Identify the structure of A to G in the following reactions. (A to D is an alcohol)

K2Cr2O7,H+ O
Δ OH

(e) E

HO O

(f) F NaCN, alcohol CH3CH2COOH

reflux

2. Draw the organic products formed in each reaction.

CH3
KMnO4, H+

d) Δ

207

PRACTICE MODULE CHAPTER 10 SK 025

CH3
KMnO4, H+

e) Δ

H3C CH3

CH3 H2O/H+

(f) H3C C C N

CH3

(g) CH2MgBr
i) CO2

ii) H2O,H+

208

PRACTICE MODULE CHAPTER 10 SK 025
3. What alcohol can be oxidized to each carboxylic acid?

4. Predict the products of the reactions when the following compounds react with acidic

solution of Na2Cr2O7. Write the equation.
(a) 1–hexanol

(b) Ethanol
(c) Acetaldehyde
(d) Hexanal

209

PRACTICE MODULE CHAPTER 10 SK 025

(e) 1–pentanol

10.4 CHEMICAL PROPERTIES
WORKSHEET 10.4

1. Identify the product form in each reactions.

O

C OH
+(a) Na

O
OH

(b) + K

(c) H3C CH3

OH + Ca

O

(d) OH + Mg

O

2. Draw the products of each acid–base reaction.

210

PRACTICE MODULE CHAPTER 10 SK 025

3. Draw the structure of product forms:

O

(a) C OH i)LiAlH4
ii) H3O+
H3C C CH3
OH O

(b) OH i)LiAlH4
ii) H3O+

O

(c) H3C i)LiAlH4
OH ii) H3O+

CH3

(d) OO i)LiAlH4

H3C OH ii) H3O+

4. Draw the structures of the labeled compounds below:

(a) O

H3C CH2 C OH PCl3 A+B

(b) H3C O PCl5

C+ D + E

H3C OH

(c) O

SOCl2 F + G +H

OH

211

PRACTICE MODULE CHAPTER 10 SK 025

+O O P2O5 I+J
H3C CH2 C OH Δ
(d)

H3C CH2 C OH

(e) O

O
HO

+ H3C C Cl pyridine K+L

O

+(f) NH3 Δ
H3C CH2 C OH M+N

O

(g)

+CH2 C OH NH2CH3 Δ O + P

CH3 O CH3

(h)
+H3C C C OH
HN CH3 Δ Q+R

CH3

212

PRACTICE MODULE CHAPTER 10 SK 025
5. Complete these esterification reactions:

WORKSHEET 10.5
1. Write the equation for the reaction between cyclobutanecarboxylic acid with:
(a) Na

(b) NaOH

(c) Mg

(d) Na2CO3

213

PRACTICE MODULE CHAPTER 10 SK 025

(e) NaHCO3

(f) LiAlH4 followed by hydrolysis

(g) PCl3

(h) methanol
(i) ethanoic acid
2. Explain the reducing property of methanoic acid

214

PRACTICE MODULE CHAPTER 10 SK 025
3. Complete the schematic diagram below

I

KMnO4,H+ Δ

H A

H3O+ Ca

O O

i) CO2 H3C B H3C
ii) H3O+
G H3C OH H3C +– CO2 + H2O

O
Na+

NH3 CH3 CH3

PCl3

F C

D
E

O O
H3C
H3C H3C
N CH3
CH3 CH3 H3C Cl + SO2 + HCl

CH3

4. Draw the structure of compound A, B and C.

C

PCC CH3

B Mg CH3CHOH A
3-phenylpropanoic acid

H+

Answer:

215

PRACTICE MODULE CHAPTER 10 SK 025

5. Fill in the blank

KMnO4, H+ K
NaOH
CH3CHCH2COOH
CH3

OH H+

6. Show the conversation by using appropriate chemical equation.

OO

CH3CHCOCH3 from CH3CHCOH

CH2CH3 CH2CH3

WORKSHEET 10.6
1. The structure of nylon 6,6 as follows. Write the equation for the formation of nylon 6,6

ANSWER:

216

PRACTICE MODULE CHAPTER 10 SK 025

2. Draw the repeating unit for the condensation polymer that is formed from the following
monomers:
a) H2N-(CH2)5-COOH

b) CH2(OH)CH2OH and HOOCC6H4COOH

WORKSHEET 10.7
MULTIPLE CHOICE QUESTIONS
Answer ALL the questions

1. Which one of these following compounds is a carboxylic acid?

A. B.
C COOC2H5

O

C. C2H5COO D. C OH

O

2. The products of the reaction of a carboxylic acid and an alcohol would be...

A. Ketone and water
B. Amide and water
C. Acid chloride and water
D. Ester and water

217

PRACTICE MODULE CHAPTER 10 SK 025

3. What is the name of the following compound?
CH3CHCH2COOH
OH

A. 1-carboxylbutanol
B. 1-carboxylbutan-2-ol
C. 3-hydroxybutanoic acid
D. 1,3-dihydroxybutanal

4. Which of the following compounds is known as 2-chlorobenzoic acid?
Cl

A. COOH C.

Cl COOH

B. CHCICOOH D. COOH

Cl

5. Which of the following alcohol can be oxidized to 2-methylpropanoic acid?
A. 2- methyl-1-propanol
B. 2-methyl-2-propanol
C. 2-butanol
D. 2-methyl-2-butanol.

6. A reaction in which a carboxylic acid reacts with a base to form a salt and water is
called _____.
A. neutralization
B. esterification
C.hydrolysis
D.saponification

7. The ester with the smell of bananas has the formula shown below
C3H7CO2C2H5

Which of the following pairs of reagent can be used to prepare this ester?
A. Propanoic acid and ethanol
B. Propanoic acid and 1-propanol
C. Ethanol and butanoic acid
D. 1-propanol and ethanoic acid

8. Which compound has the highest boiling point?
A. Butane
B. Propanone
C. Acetic acid
D. 1-propanol

218

PRACTICE MODULE CHAPTER 10 SK 025

9. What factor can decrease the solubility of carboxylic acid in water?

A. The increase in length of the hydrocarbon chain.
B. The decrease in length of the hydrocarbon chain.
C. The increase in number of carboxyl group.
D. The number of hydrogen bond.

10. Choose the correct statement.

A. Ethanoic acid is completely soluble in water because it can dimerise in the presence of
water.

B. Ethanoic acid is completely soluble in water because it has 2 carbon atoms.
C. Ethanoic acid is completely soluble in water because it can form hydrogen bond and

van der Waals forces with water molecules.
D. Ethanoic acid is completely soluble in water because it has small hydrophobic group.

WORKSHEET 10.8

MODEL OF PSPM QUESTIONS

1 a) Benzoic acid , X reacts with magnesium metal to give magnesium benzoate,Y.
Reduction of X with LiAIH4 followed by hydrolysis produces Z. Acid catalysed
esterification of X with ethanol forms W. Treatment of X with SOCI2 gives V,
whereas neutralization of X with KOH produces T. Reaction of X in ammonia with
strong heating yields U. Draw the structures of T, U , V, W, X, Y and Z.

[7 marks]

b) Explain why 3-chlorobenzoic acid has higher acidity than benzoic acid.

[2 marks]

2 (a) Consider the reaction scheme given below:

(i) Write the structural formulae for R, S and T.
219

PRACTICE MODULE CHAPTER 10 SK 025

(ii) State the reagents I and II.

(b) Explain the following observations: [5 marks]
[4 marks]
(i) Methanoic acid decolourises the purple colour of potassium

permanganate solution.

(ii) Methanoic acid has higher acidity than methanol.

3 (a) Treatment of 2-methylbutanoic acid with alcohol W give an ester X with molecular
formula of C7H14O2 . Alcohol W reacts with alkaline iodine solution to form yellow precipitate Y,
whereas oxidation of W by using strong oxidizing agent yield Z

(i) Draw the structures for W, X and Z.
(ii) Write the chemical equation to produce ester X.

[4 marks]

(b) The reaction scheme below show the formation of 2-ethylcyclohexanecarboxylic acid
from 1-ethylcyclohexene. Give the reagents AA and CC and draw the structural
formulae of BB.

(c) 2-methylpentanedioic acid more soluble in water compared to butanoic acid. Explain your
answer.

[5 marks]

Prepared by : Mdm Noor Shuhada bt Rahim
Checked by : Mdm Noor Asmahan Abdullah & Mdm Julianawati

220

PRACTICE MODULE CHAPTER 11 SK025

CHAPTER 11: AMINE

REACTION OF AMINE COMPOUNDS

i) LiAlH4 O HCl
ii)H2O S Cl
@H2/Pt CH3CH2CH2NH2 O

i) LiAlH4 excess KOH
ii) H2O
NaNO2
Br2, NaOH HCl

Zn/HCl NH2 O HCl
@SnCl2/HCl S Cl OH
O
@Fe/HCl
excess KOH

Br2 (aq) NaNO2, HCl
below 5 °C

HINSBERG TEST O excess KOH HCl
S Cl HCl
CH3 O HCl

H N H+

CH3 O excess KOH
S Cl
CH3 N H + O

CH3 O excess KOH
S Cl
CH3 N CH3 + O

221

PRACTICE MODULE CHAPTER 11 SK025

NITROUS ACID TEST

NH2 NaNO2, HCl
0-5 °C

H NaNO2, HCl
N CH3 0-5 °C

CH3 NaNO2, HCl
N CH3 0-5 °C

CH3 NaNO2, HCl
HN H

CH3 NaNO2, HCl
CH3 N H

CH3 NaNO2, HCl
CH3 N CH3

222

PRACTICE MODULE CHAPTER 11 SK025

11.1 : INTRODUCTION TO AMINE

WORKSHEET 11.1

1. Complete the table below

Class of amine General Formula Example

Primary (1o) R NH2

Secondary (2o) 1

R
RNH

Tertiary (3o) 1

R

R N 2

R

2. Give the IUPAC nomenclature and class of amine for the following structure.

Structure IUPAC Nomenclature class
2o
H
H3C CH2N CH2 CH3

CH3NH2 1o
2o
CH3NHC2H5 3o
1o
(CH3)3N 2o
1o
CH3CH2NH2
3o
CH3CH2CH2CH2NHCH2CH3 3o

CH3CH(CH3)CH2CH2CH2N
H2

(CH3)2NCH2CH2CH3)

CH3
H3C CH2 CH2 N

CH2 CH3

223

H3C PRACTICE MODULE CHAPTER 11 SK025
H3C C CH3 1o
1o
NH2
1o
H3C CH3 1o
1o
NH2 1o
2o
NH2
2o
NH2
224
H3C

H2N NO2

H2N NH2

H
N CH3

H
N

CH3 PRACTICE MODULE CHAPTER 11 SK025
H3C N 3o

CH3 1o
H3C HC CH CH3

NH2

3. Draw the structure for the following IUPAC name.

Compound Structural Formula

a) 4-Aminobenzoic acid

b) N-Ethyl-N-methylaniline

c) 3-Methyl-1-butanamine

d) 4-Amino-1-butanol

e) 4-Methyl-3-nitroaniline

f) 4,4-Dimethylcyclohexanamine

g) 2-chloroaniline

225

PRACTICE MODULE CHAPTER 11 SK025

11.2 PHYSICAL PROPERTIES OF AMINES

WORKSHEET 11.2

1. The structural formulae of several amines A to D are shown below.

H2N CH3NH2 NH2 CH3CH2CH2NH2
H3C CH CH3 B C D

A

Which of the above
a) Dissolve easily in cold water?

b) Dissolve in aqueous HCl?

c) Has the highest boiling point?

2. Which compound has the higher boiling point, CH3CH2CH2CH2CH2NH2 or
CH3CH2CH2CH2CH2CH3? Explain.

3. Which compound is more soluble in water, CH3CH2CH2CH2CH3 or CH3CH2NHCH2CH3?
Explain.

4. Arrange the following compounds in order of increasing boiling point.

W: CH3CH2CH2NH2 Y: CH3NH2

X : (CH3)3N Z: CH3NHCH2CH3

5. Arrange the following compounds in ascending order of boiling points. Explain your answer.
N,N-dimethylmethanamine, 1-propanamine, n-butane, 1-propanol

226

PRACTICE MODULE CHAPTER 11 SK025

11.3 : Preparation of amine
WORKSHEET 11.3

1. How would you prepared the following amine? Some of the preparations may involve
more than one step.
a. Phenylmethanamine (benzylamine) from benzamide
b. Methylamine from ethanamide

227

PRACTICE MODULE CHAPTER 11 SK025
c. 2-Propanamine from 2-methylpropanamide
d. N-Butylaniline from butanoyl chloride
e. Phenylethanamine(C6H5CH2CH2NH2) from benzyl bromide (C6H5CH2Br)

2. Using a suitable haloalkane, suggest two different methods to prepare propylamine in the
laboratory.

3. Suggest how ethanol can be converted to ethylamine. Write an equation for the reaction.

228

PRACTICE MODULE CHAPTER 11 SK025

11.4: CHEMICAL PROPERTIES OF AMINE

WORKSHEET 11.4

1. Identify A to E in the following reactions.

a)

A + Br2 NaOH +H3C CH2 CH2 NH2 CO32-
H2O

O i. LiAlH4 B
C NH2 ii. H2O

b) H2

C Ni H3C CH CH2CH2 CH2 NH2
CH3

c) NH2

NO 2

D

d) E + 3HBr

NH2 O
HN C CH3
+ Br2(aq)
+ 2HCl
e)
O C CH3
NH2 O

+F

OH

f) + N Cl-

G N

HNO2 + NaCl + H2O
0 - 5 °C

g)

229

PRACTICE MODULE CHAPTER 11 SK025
2. Give the structural formulae of the organic products when the following pairs of organic

compounds react.
(a) Ethylamine and benzoyl chloride

(b) 1-Propanamine and benzenesulphonyl chloride in KOH

(c) N-Methylaniline and nitrous acid

(d) 4-Methylaniline and hydrochloric acid

(e) 2-Methylaniline and bromine water

3. The following reaction scheme shows the synthesis of an azo compound using benzene

as the starting material.

NO 2 NH2 +-

N2 Cl

i ii iii iv

azo compound

P Q Benzenediazonium
chloride

a) Name compounds P and Q

230

PRACTICE MODULE CHAPTER 11 SK025
b) State the reagent and condition I to iv .
c) Draw the structural formula of the azo compound form. Give the use of the azo

compound.

11.5 : CHEMICAL TEST
WORKSHEET 11.6

1. Suggest a chemical test to differentiate between following compound
a) Butylamine and diethylamine

231

PRACTICE MODULE CHAPTER 11 SK025
b) Ethylamine and dimethylamine

c) Ethylamine and phenylamine

232

d) PRACTICE MODULE CHAPTER 11 SK025
and (CH3CH2)2NH
H3C N
CH3

WORKSHEET 11.6
MULTIPLE CHOICE QUESTIONS
Answer ALL the questions

1. Which of the following compounds is a secondary amine?
A CH3CH2NH2
B (CH3CH2)3N
C CH3CH2NHCH3
D CH3CH2N(CH3)C6H5

2. What is the name of the following compound?

CH2 CH3
N

CH3

A. N-ethyl-N-methylphenylamine
B. N-methyl-N-ethylphenylamine
C. N-ethyl-N-methyl-N-phenylamine
D. N-methyl-N-phenylethylamine

233

PRACTICE MODULE CHAPTER 11 SK025

3. Which of the following amines has the highest boiling point?

A. CH3CH2NH2
B. CH3CH2-NHCH2
C. H2NCH2CH2NH2
D. (CH3CH2)3N

4. Compound X is an amine with four carbon atoms. Which of the following statements
regarding X is not true?
A. X has a fishy, ammoniacal odour.
B. X is more volatile than butanoic acid.
C. X has a higher boiling point than butan-1-ol.
D. X is more soluble in water than cyclobutane.

5. The following reaction scheme shows how two different amines can be prepared from
bromoethane.

CH3CH2Br I
CH3CH2CH2NH2

II CH3CH2NH2

Which of the following are the reagents I and II?
I II

A CH3NH2 H2

B KCN, H2/Ni NH3

C HCN, H2/Pt LiAlH4

D CH3NH2 CH3Cl

6. Which of the following compounds will liberate nitrogen when a mixture of sodium
nitrate(III) and hydrochloric acid is added to it?
A. C6H5CH2COOH
B. CH3CH2CONH2
C. CH3CH2NH3+CI-
D. C6H5CH2NHCH3

234

PRACTICE MODULE CHAPTER 11 SK025

7. Which of the following is converted into an alcohol on treatment with HNO2?
A. Methyl amine
B. Aniline
C. Dimethyl amine
D. Triethyl amine

8. Which of the following reagents can be used to distinguish between the above
compounds?

NH2 NH2

A. Br2
B. HNO2
C. KOH
D. CH3COCI

9. An organic compound X has the following chemical properties:
• Decolourises aqueous Br2
• Reacts with CH3COBr to produce HBr

Which of the following compounds is.X?

A. C6H5NH2
B. CH3CH2CH2NH2
C. CH2=CHCH2N(CH3)2
D. CH3CH2NH2

10. Aniline on treatment with excess of bromine water, which of the following will
produce?

A. Aniline bromide
B. o-bromoaniline
C. p-bromoaniline
D. 2, 4, 6-tribromoaniline

11. Which of the following is obtained when the following compound is heated with
nitric(III)acid?

O
H2N C

NH2

235

PRACTICE MODULE CHAPTER 11 SK025

O O O
HO C H2N C HO C

OH N2Cl NH2

A. B. C. D.

O
C
H2N

OH

WORKSHEET 11.8

MODEL OF PSPM QUESTIONS

1. Putrescine, H2NCH2CH2CH2CH2NH2 is an amine produced by the bacterial decay of protein
in meat. It can be synthesised by the reduction of compound X with H2/Pt or LiAlH4 and by
the reduction of compound Y using LiAlH4. Hofmann degradation of compound Z can also
produce putrescine.

Based on the information above, deduce the structural formulae of X, Y and Z and state the
reagent used in Hofmann degradation.

What are the products formed when putrescine is reacted with HCl?

[6 marks]

2. Compounds GG, HH and JJ are isomers with a molecular formula of C4H11N. JJ is formed
from the reaction of 1-chloropropane with sodium cyanide, 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 formed which dissolve upon
acidification. Deduce the structural formulae of GG, HH, JJ and KK. Give your reasons.

[7 marks]

3. Show how you would differentiate methanamine from N-methylmethanamine.

[7 marks]

Prepared by : Mdm Wan Rosilah
Checked by : Mdm Noor Asmahan

236

PRACTICE MODULE CHAPTER 12 SK025

CHAPTER 12: AMINO ACID
i-Think Map / Mind Map

Zwitterions and Isoelectronic Point

H O HO OH- HO
C C OH
H3N+ R H3N+ C C O- H2N C C O-
H+ R R

cation zwitterion anion

pH < pI pH = pI pH > pI

acidic medium neutral basic medium

237

PRACTICE MODULE CHAPTER 12 SK025

Reactions in Amino Acids

O

H3N+ CH C O CH2 CH2CH3

CH3 
CH3CH2CH2OH,H+

O NaNO2, HCl O HCl O
below 0 °C H2N CH C OH Cl-H3N+ CH C OH
+N2 HO CH C OH CH3
CH3
CH3
NaOH
+

O

Cl CH C OH H2N O
CH3 CH C O- Na+
+ CH3
O

H2C CH C OH

12.1 : INTRODUCTION TO AMINO ACIDS

WORKSHEET 12.1

1. Glycine is an example of α-amino acid.
COOH

H C NH2
H Gly

i. Why glycine known as α-amino acid?

ii. Give the IUPAC name for glycine?

2. Name the given amino acid according to the IUPAC name.

CH3 O

CH CH2 CH C OH

i. CH3 NH2

___________________________________

238

PRACTICE MODULE CHAPTER 12 SK025

OH O

CH2 CH CH C OH

ii. CH3 NH2

______________________________________

OO
HO C CH2CH2 CH C OH
iii. NH2

________________________________________

O

CH2CH C OH

NH2
iv.

_________________________________________

WORKSHEET 12.2

1. Isoleucine, with an isoelectric point of 6.02 has the following structure

O OH
CH3 CH2 CH CH C

H3C NH2

a. Draw the structural formula of isoleucine at
i. pH 6.02

ii. pH 4.00

239

PRACTICE MODULE CHAPTER 12 SK025

iii. pH 10.30

2. The isoelectronic point (pI) of phenylalanine is 5.5. Draw the structure of major form of
phenylalanine at pH values of 1, 5.5 and 11.
O
CH2CH C OH
NH2
Answer:
pH values of 5.5 =

pH values of 1 =

pH values of 11 =

3. Valine is the traditional name of the organic compound with the structural formula shown
below.
O
CH3 CH CH C OH
CH3 NH2
a) What is the IUPAC name of valine?

b) What are the functional group present in Valine?

c) Write the formula of the species formed when Valine is dissolved in acidic solution and
alkaline solution?

240

PRACTICE MODULE CHAPTER 12 SK025

4. Write ionic equations to show the reactions between alanine with an acid and a base.
COOH

H C NH2
CH3

Answer:
Reactions between alanine with an acid:

Reactions between alanine with a base:

12.2 CHEMICAL PROPERTIES OF AMINO ACIDS
WORKSHEET 12.3

1. Glycine is the simplest amino acid. What is the product form when glycine react with
a) HCl

b) nitrous acid

241

PRACTICE MODULE CHAPTER 12 SK025
c) ethanol in the presence of acid catalyst
2. Explain the following statements and write the equation involved.
a) Amino acid react with hydrochloric acid.

b) Amino acid react with methanol in acidic medium.

c) Amino acid react with sodium hydroxide

3. Draw the structure of the products of a valine, with
a) CH3CH2CH2OH, H+
b) NaOH

242

PRACTICE MODULE CHAPTER 12 SK025

c) HCl
d) LiAlH4, H3O+

4. Isoleucine, 2-amino-3-methylpentanoic acid is an α-amino acid.
a) Give the reaction equation between isoleucine and
i) Nitrous acid

ii) KOH

b) What is the product of the reaction between Isoleucine and acidified 2-propanol?

243

PRACTICE MODULE CHAPTER 12 SK025
WORKSHEET 12.4

1. The structure of dipeptide is shown below;
OO

H2NCHC NHCHC OH
CH2OH CH2
CH2 NH2

(a) What is the name of chemical bond linking the amino acid together in the dipeptide?

(b) Draw the structural formula of the amino acid at the
(i) N-terminal

(ii) C-terminal

2. Phenylalanine (2-amino-3-phenylpropanoic acid) is an amino acid. Two molecules of
phenylalanine react to form a dipeptide. Draw the structure of the dipeptide formed. Is the
dipeptide optically active? Explain.
Answer:

244

PRACTICE MODULE CHAPTER 12 SK025

3. Show the formation of peptide linkage between 2-aminoethanoic acid and 2-aminopropanoic
acid. Is the peptide a dipeptide or tripeptide or polypeptide? Explain your answer.

WORKSHEET 12.5

MULTIPLE CHOICE QUESTIONS

Answer ALL the questions

1. The IUPAC name for compound below is

CH3 O
CH3 CH2 CHCH C OH

NH2
A. 2-amino-3-methylpentanoic acid
B. 1-carboxyl-2-methylbutanamine
C. 2-amino-3-isobutylethanoic acid
D. 4-amino-3-methylpentanoic acid

O O
H2N CH C NH CH2 C OH
2. CH3
react with the following reagents except

A. HCl
B. NaOH
C. H2O
D. NaNO2 / HCl

245

PRACTICE MODULE CHAPTER 12 SK025

3. Which compound is most soluble in water
A. 2-propanamine
B. propanoic acid
C. 2-aminopropanoic acid
D. 2-propanol

4. Lysine is the common name for 2,6-diaminohexanoic acid. The formula of lysine is
A. H2N(CH2)4CH(NH2)COOH
B. H2N(CH2)6CH(NH2)COOH
C. H2NCH(NH2)CH2CH2CH2COOH
D. CH3CH(NH2)(CH2)2CH(NH2)COOH

5. Both the organic compounds, HOCH2COOH and H2NCH2COOH
A. are insoluble in water
B. form zwitterions
C. react with aqueous sodium hydroxide
D. react with hydrochloric acid

6. Which of the following compounds has the following properties?
• Has a high melting point
• Is soluble in water
• Has no effect on litmus solution

A. H2NCH2COOH
B. H2NCH(CH2COOH)COOH
C. H2NCH(CH2OH)CH2OH

H2N

D. NH2
E.

For the questions 7 and 11, use this table to select the correct answer.

A BC D
I only I and II only II and III only I, II and III

7. Which of the following statements about glycine is/are correct?
I It forms dipolar ions in an aqueous solution
II It react with hydrochloric acid at room temperature
III It dissolves readily in organic solvents
Answer :

8. An amino acid has the structural formula C6H5CH2CH(NH2)COOH. It can be inferred that
I It contains a peptide bond
II It undergoes a neutralization reaction with aqueous sodium hydroxide at room
temperature
III It react with nitrous acid to liberate nitrogen gas.

246