Chem a2 Tutorial 1 Benzene and Its Derivatives

Page 1 A2 Chemistry Tutorial 1

Chemistry A2 Tutorial 1: Benzene and its derivatives

Question 1. Complete the table below with the correct formula

Name and Molecular formula

Structural formula Skeletal formula Empirical Formula

Benzene C6H6

Methylbenzene

Ethylbenzene

Nitrobenzene

1,3-dinitrobenzene

Cyclohexane

Cyclohexene


2. (a) Benzene reacts with concentrated nitric acid in the presence of a catalyst to form nitrobenzene. This is an electrophilic substitution reaction.

(i) Write an equation for the overall reaction.

..................................................................................................................... (1)

(ii) State the name of the catalyst used.

..................................................................................................................... (1)

(iii) Write the formula, including its charge, of the electrophile involved in the reaction.

..................................................................................................................... (1)

(b) Benzene reacts with chlorine gas in the dark and in the presence of a catalyst to form chlorobenzene. This is an electrophilic substitution reaction.


..................................................................................................................... (1)


..................................................................................................................... (1)


..................................................................................................................... (1)

(c) Benzene reacts with chloroethane in the presence of a catalyst to form ethylbenzene. This is an electrophilic substitution reaction.


..................................................................................................................... (1)



..................................................................................................................... (1)


..................................................................................................................... (1)

(d) Benzene reacts with ethanoyl chloride in the presence of a catalyst to form phenylethanone. This is an electrophilic substitution reaction.


..................................................................................................................... (1)


..................................................................................................................... (1)


..................................................................................................................... (1)

(e) Benzene reacts with bromine liquid in the dark and with the presence of a catalyst to form bromobenzene. This is an electrophilic substitution reaction.


..................................................................................................................... (1)


..................................................................................................................... (1)


............................................................................................................... (1)


(f) Benzene reacts with hydrogen gas to form cyclohexane in the presence of a catalyst.


..................................................................................................................... (1)


..................................................................................................................... (1)

(iii) Name the type of organic reaction that occurs in this reaction.

...............................................................................................................(1)


Question 3. Nitration of Benzene Nov 2002 Paper 4


Question 4 Benzene can be converted into chlorobenzene by a chlorination reaction. (a) State the reagents and conditions necessary to carry out this reaction. .......................................................................................................................................... ......................................................................................................................................[2] (b) What type of reaction mechanism is this? ......................................................................................................................................[1]

(c) The reaction proceeds via two steps:

+

Y

+ Z +

(i) Draw the structure of the intermediate Y in the box. (ii) Identify the cation X+.................................................................................................. (iii) Identify the cation Z+.................................................................................................. (iv) Write an equation to show how X+ is produced from the reagents. ...................................................................................................................................[5]

Cl


Question 5 Benzene can be converted into methylbenzene by a Friedel-Crafts alkylation reaction. (a) State the reagents and conditions necessary to carry out this reaction. .......................................................................................................................................... ......................................................................................................................................[2] (b) What type of reaction mechanism is this? ......................................................................................................................................[1]


+

Y

+ Z +


CH3


Question 6 Benzene can be converted into phenylethanone by a Friedel-Crafts acylation reaction. (a) State the reagents and conditions necessary to carry out this reaction. .......................................................................................................................................... ......................................................................................................................................[2] (b) What type of reaction mechanism is this? ......................................................................................................................................[1]


+

Y

+ Z +


C

O CH3


Question 7

Reaction I : Methylbenzene 2-Bromomethylbenzene

Reaction II : Methylbenzene 2-Chloromethylbenzene

Reaction III : Methylbenzene 2-Nitromethylbenzene

a) Give the following formula for Methylbenzene:

(i) Structural formula: ………………… ……………………….1

(ii) Molecular formula: ……………………………………………1

(iii) Empirical formula: ……………………………………………1

b) Methylbenzene is categorized as an aromatic hydrocarbon molecule (i) Define the term hydrocarbon molecule.

………………………………………………………………………………………………………………………………………………….……1

(ii) Then explain why methylbenzene is categorised as a aromatic molecule.

………………………………………………………………………………………………………………………………………………….……1

c) Name the type of organic reaction that occurred in reaction labeled I, II and III.

………………………………………………………………………………………………………………………………………………….……1

d) State the appropriate reagent and condition for reaction labeled as:-

(i) I :……………………………………………………………………..

(ii) II :……………………………………………………………………..

(iii) III :……………………………………………………………………..


e) Write a balanced equation for reaction labeled as:

(i) I :……………………………………………………………………………………………………………………1

(ii) II :……………………………………………………………………………………………………………………1

(iii) III :……………………………………………………………………………………………………………………1

f) Describe the mechanism of reactionI, stating the following clearly:

Labelled active species, show the Movement of electrons, Organic intermediate structure and By-product

5

Methylbenzene Active

Species

Organic intermediate

2-Bromomethylbenzene By-product

Draw and name one other structural isomers of 2-chloromethylbenzene that is also formed

in the monochlorination reaction of reaction II. 2m

Structural formula

Systematic name


Question 8

Reaction I : Methylbenzene 2-Bromomethylbenzene

Reaction II : Methylbenzene 2-Chloromethylbenzene

Reaction III : Methylbenzene 2-Nitromethylbenzene

a) Name the type of organic reaction that occurred in reaction labeled I, II and III.

………………………………………………………………………………………………………………………………………………….……1

b) State the appropriate reagent and condition for reaction labeled as:-

(i) I :……………………………………………………………………..

(ii) II :……………………………………………………………………..

(iii) III :……………………………………………………………………..

c) Write a balanced equation for reaction labeled as:

(i) I :……………………………………………………………………………………………………………………1

(ii) II :……………………………………………………………………………………………………………………1

(iii) III :……………………………………………………………………………………………………………………1

d) Describe the mechanism of reaction III stating the following clearly:Labelled active species,

show the Movement of electrons, Organic intermediate structure and By-product 5

Methylbenzene Active

Species

Organic intermediate

+

2-Bromomethylbenzene By-product


e) Draw and name one other structural isomer that is produced in reaction I and reaction III.

2m

Reaction I III

Structural isomer

Systematic name

Question 9

Molecule U

Reaction 1

Molecule X

Reaction 2

Molecule V

Reaction

3

Molecule W


a) Give the systematic name of molecule labeled as:

(i) Molecule U :……………………………………………………………………………1

(ii) Molecule V :……………………………………………………………………………1

(iii) Molecule W :……………………………………………………………………………1 b) Give the molecular formula(not structural formula) for molecule labelled as:

(i) Molecule U :……………………………………………………………………………1

(ii) Molecule V :……………………………………………………………………………1

(iii) Molecule W :……………………………………………………………………………1

(iv) Molecule X :……………………………………………………………………………1

c) State the reagent and conditions for reaction labeled as :

(i) Reaction 1 :…………………………………………………………………………….…………1

(ii) Reaction 2:…………………………………………………………………………..……………1

(iii) Reaction 3:…………………………………………………………………………..……………1

d) Name the type of organic reaction occurred in reaction labelled Reaction 1.

………………………………………………………………………………………………………………………………..1

e) Name the type of organic reaction occurred in reaction labelled Reaction 2.

………………………………………………………………………………………………………………………………..1


Question 10

a) Based on the reaction shown

(i) Name the type of reaction

………………………………………………………………………………………………………………………………..1

(ii) State the reagents and conditions for this change

………………………………………………………………………………………………………………………………..1

b) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

c) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1


d) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

e) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

e) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1


f) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

g) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

h) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1


i) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

j) Based on the reaction shown


………………………………………………………………………………………………………………………………..1


………………………………………………………………………………………………………………………………..1

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Chem a2 Tutorial 1 Benzene and Its Derivatives

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