Unit 4 Benzene MT

Question 1

Name the compound.

Answer 1

1,3-dimethylbenzene

Question 2

The enthalpy change for the hydrogenation of cyclohexene to cyclohexane is -120kJmol^-1. What would the expected enthalpy change for the hydrogenation of benzene be if it was cyclohexa-1,3,5-triene? Why is it different to this value?

Answer 2

-36kJmol^-1.

Benzene is more stable than cyclohexa-1,3,5-triene due to delocalisation of some of its electrons.

Question 3

Name the compound.

Answer 3

Nitrobenzene.

Question 4

What is the mechanism for electrophilic substitution of NO₂⁺ with benzene?

Answer 4