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CAIE A-Level Chemistry A2 34.2 Phenylamine and Azo Compounds Questions

Practise phenylamine synthesis, basicity, diazotisation and azo coupling through conditions and structures.

Syllabus
2028–2030
Course
Chemistry 9701
Level
A2

Exam points

  • select reagents and temperatures for preparing phenylamine, forming a diazonium salt and coupling it
  • compare phenylamine basicity by deciding whether the nitrogen lone pair is available to accept H+
  • draw diazonium, phenol or azo products while retaining other substituents shown in a synthesis route

Covered syllabus points

34.2.1—Preparation of phenylamine via the nitration34.2.2—Describe34.2.3—Basicities of aq. ammonia, ethylamine34.2.4—About azo compounds

Question 1

[Maximum number: 4]

Potassium iodide, KI, is used as a reagent in both inorganic and organic chemistry.

Question (a)

(a)

KI\quad \mathrm{KI} is used as a source of I−\mathrm{I}^{-} ions in organic synthesis.

One example of this is shown in the synthetic route in Fig. 1.1.

Fig. 1.1

Fig. 1.1

[ 4 ]

Question (i)

(i)

Identify the reagents required for steps 1 and 2 .
step 1
step 2

[ 2 ]

Question (ii)

(ii)

Step 3 occurs in two stages.
stage I NaNO2\mathrm{NaNO}_{2} and HCl undergo an acid-base reaction to produce HNO2\mathrm{HNO}_{2}.
stage II HNO2\mathrm{HNO}_{2} reacts with C,C6H5NH2\mathbf{C}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, to produce D,C6H5 N2+\mathbf{D}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}_{2}{ }^{+}.
Complete the equations for stage I and for stage II.

stage I NaNO2+HCl→\mathrm{NaNO}_{2}+\mathrm{HCl} \rightarrow

stage II

[ 2 ]

Question 2

[Maximum number: 8]

Question (a)

(a)

Benzene can be used as a starting material to produce phenylamine by a two-step synthesis.

Figure for Question (a) — CAIE A-Level Chemistry A2
[ 2 ]

Question (i)

(i)

Give reagents and conditions for the production of phenylamine from nitrobenzene in step 2.

[ 2 ]

Question (b)

(b)

Phenylamine reacts with Br2(aq)\mathrm{Br}_{2}(\mathrm{aq}).

[ 3 ]

Question (i)

(i)

Write an equation for this reaction. You may use structural or displayed formulae.

[ 1 ]

Question (ii)

(ii)

Name the organic product of this reaction.

[ 1 ]

Question (iii)

(iii)

Describe two observations that can be seen when phenylamine reacts with Br2(aq)\mathrm{Br}_{2}(\mathrm{aq}). observation 1 observation 2

[ 1 ]

Question (c)

(c)

Describe the relative basicities of ammonia, ethylamine and phenylamine, starting with the least basic.
Explain your answer in terms of their structures. < <
least basic
most basic

[ 3 ]

Question 3

[Maximum number: 1]

Cumene is an aromatic hydrocarbon used in the synthesis of other useful chemicals.

cumene

cumene

Fig. 5.4 shows two reactions of phenol.

Fig. 5.4

Fig. 5.4

Name the functional group that is formed in reaction 3 .

Question 4

[Maximum number: 2]

Potassium iodide, KI, is used as a reagent in both inorganic and organic chemistry.

KI\quad \mathrm{KI} is used as a source of I−\mathrm{I}^{-} ions in organic synthesis.

One example of this is shown in the synthetic route in Fig. 1.1.

Fig. 1.1

Fig. 1.1

Identify the reagents required for steps 1 and 2 .
step 1
step 2

Question 5

[Maximum number: 2]

Potassium iodide, KI, is used as a reagent in both inorganic and organic chemistry.

KI\quad \mathrm{KI} is used as a source of I−\mathrm{I}^{-} ions in organic synthesis.

One example of this is shown in the synthetic route in Fig. 1.1.

Fig. 1.1

Fig. 1.1

Step 3 occurs in two stages.
stage I NaNO2\mathrm{NaNO}_{2} and HCl undergo an acid-base reaction to produce HNO2\mathrm{HNO}_{2}.
stage II HNO2\mathrm{HNO}_{2} reacts with C,C6H5NH2\mathbf{C}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}, to produce D,C6H5 N2+\mathbf{D}, \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{~N}_{2}{ }^{+}.
Complete the equations for stage I and for stage II.

stage I NaNO2+HCl→\mathrm{NaNO}_{2}+\mathrm{HCl} \rightarrow

stage II

Question 6

[Maximum number: 3]

Describe the relative basicities of ammonia, ethylamine and phenylamine, starting with the least basic.
Explain your answer in terms of their structures. < <
least basic
most basic

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