1.1. The energy change for hydrogenation of cyclohexene is -120 kJ mol^-1. However, when benzene undergoes hydrogenation, the energy change is 152 kJ mol^-1 less than expected. 

Use this data to explain the relative stabilities of benzene and the theoretical cyclohexa-1,3,5-triene molecule. 

1.2. When cyclohexa-1,3-diene undergoes hydrogenation it will have a different value than expected. 

Using the data given in part a) explain why cyclohexa-1,3-diene has a different value than expected and suggest a value for the energy change for this reaction.

1.3. Explain why the energy change for the hydrogenation of cyclohexa-1,4-diene will be different from the value for the hydrogenation of cyclohexa-1,3-diene.