Phenol (Cambridge (CIE) A Level Chemistry): Exam Questions

Phenol behaves as a weak acid.

i) Construct the equation for the reaction of phenol with sodium hydroxide.

[1]

ii) Construct the equation for the reaction of phenol with sodium metal.

[1]

Phenol undergoes electrophilic substitution when reacted with bromine water at room temperature.

State two observations that can be made during this reaction.

Draw the skeletal formulae of the two possible products from the reaction of phenol with dilute nitric acid.

State why 3-nitrophenol is not formed when phenol reacts with dilute nitric acid.

Phenol is an aryl compound.

State the molecular formula of phenol.

Explain why phenol is a weak acid. 

You should include an equation in your answer. 

Describe and explain how the acidities of ethanol and phenol compare with that of water.

Phenol reacts with bromine water.

i) State the name of the product formed.

[1]

ii) Construct a balanced chemical equation for this reaction.

[1]

Compare the reagents and conditions required for the bromination of phenol and benzene. Use your answer to explain how these reactions show that phenol is more reactive than benzene.

Phenol can be prepared from phenylamine.

There are three stages that take place during this preparation:

• Stage 1: Prepare nitric(III) acid using sodium nitrate and hydrochloric acid

• Stage 2: React phenylamine with nitric(III) acid and hydrochloric acid to form a diazonium salt

• Stage 3: Thermal decomposition of the diazonium salt to form phenol, hydrochloric acid, and nitrogen gas

i) State the essential conditions for the reaction in stage 2.

[1]

ii) Draw the skeletal formula of the diazonium salt formed in stage 2.

[3]

Construct balanced equations for the reactions that occur at each stage.

Stage 1:

Stage 2:

Stage 3:

The diazonium salt formed during stage 2 can also react with phenol to form a useful substance, Z.

i) Draw the skeletal formula of Z.

[2]

ii) Suggest a possible use for Z.

[1]

The first step of substance Z involves creating the diazonium ion. 

The reaction is the same as that in stage 2 in part (a). 

Explain why the reaction to produce the diazonium ion is carried out at below 10 ^oC. 

Rodinol can be synthesised from phenol by the following route:

i) State the reagents and conditions for step 1.

[1]

ii) Name the reaction mechanism for step 1.

[1]

i) State the type of reaction that occurs in step 2.

[1]

ii) State the reagents and conditions for step 2.

[2]

Rodinol can undergo many reactions.

Draw the skeletal formulae of compounds E, F and G from the reaction chart of rodinol shown below.

This question is about the reactions of phenol and benzene. 

Explain the difference in bromination of phenol and benzene. In your answer, include structures of any organic products formed in the reaction. 

A mixture of 2-nitrophenol and 4-nitrophenol can be formed via the pathway shown in Fig. 1.1.

Fig. 1.1

i) State the reagents and conditions required for reaction 1.

[1]

ii) Calculate the mass, in grams, of phenol required to form 30 g of 2-nitrophenol assuming a 35% yield. Give your answer to three significant figures and show your working.

mass = ............... g

[3]

Phenol reacts with sodium to form a salt and hydrogen gas in an acid-base reaction.

Explain why phenol behaves as a weak acid.

Phenyl 2-hydroxybenzoate is an antiseptic and is shown in Fig. 2.1.

Fig. 2.1

A molecule of phenyl 2-hydroxybenzoate has 13 carbon atoms

i) State the number of carbon atoms that are sp, sp² and sp³ hybridised carbon atoms, if any, in phenyl 2-hydroxybenzoate.

[1]

 ii) Complete Table 2.1 showing the reactions of phenyl 2-hydroxybenzoate with the two reagents.

 Table 2.1

[3]

Phenyl 2-hydroxybenzoate can be made from 2-hydroxybenzoic acid and phenol by heating the two compounds strongly together.

Construct an equation, using skeletal formulae, for this reaction.

Complete and balance the equation in Fig. 2.2 for the alkaline hydrolysis of phenyl 2-hydroxybenzoate using excess NaOH.

Fig. 2.2

Mesalamine can be synthesised from salicylic acid, the chemical structure of which is shown in Fig. 3.1.

Fig. 3.1

i) State the systematic name for salicylic acid.

[1]

ii) Deduce the names and structures of the two positional isomers of salicylic acid that are possible.

[2]

A possible two step synthesis of mesalamine is shown below in Fig. 3.2.

Fig. 3.2

Draw the skeletal formulae of compound X and mesalamine.

State the reagents and conditions required for steps 1 and 2 in Fig. 3.2 in part (b).