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(a)

3 Mark s

This question is about benzene and some of its compounds.

In 1865, Kekulé suggested that the benzene molecule was a six-membered

carbon ring with alternate double and single bonds.

However, this suggestion did not fully explain the structure and stability of benzene.

State and explain three different types of evidence that led to this structure of benzene

being rejected, in favour of benzene with a ring of delocalised electrons.

(b)

4 Mark s

Benzene reacts with a mixture of concentrated nitric acid and

concentrated sulfuric acid to form nitrobenzene.

Give the mechanism for this reaction, including an equation for the formation

of the electrophile.

(b) (I)

(b) (II)

2 Mark s

The preparation of nitrobenzene is usually carried out between 50 °C and 60 °C.

Explain why the temperature used should not be higher or lower.

2 Mark s

Benzene reacts with pure bromine when heated under reflux in the presence of a

Friedel-Crafts catalyst. Phenol reacts with bromine water at room temperature.

Write the equation for the reaction between phenol and excess bromine water.

2 Mark s

Explain why phenol reacts with bromine under much milder conditions than

those required for the reaction between benzene and bromine.

(d) (I)

2 Mark s

1-chloro-1-phenylethane is found in some fruits, such as apples, and is used to

make fragrances.

It can be synthesised from benzene in three steps.

Identify, by name or formula, the reagent and catalyst used in Step 1.

(d) (II)

1 Mark

Draw the structure for Compound X

(d) (III)

1 Mark

Identify, by name or formula, the reagent used in Step 2.

(d) (IV)

1 Mark

Identify, by name or formula, the reagent used in Step 3.