Introduction to arenes

What are arenes?

Hydrocarbons based on benzene, C₆H₆

What is the IUPAC name for Kekulé's structure of benzene?

Cyclohex-1,2,3-triene

What is hydrogenation?

Adding a hydrogen molecule to an unsaturated hydrocarbon for it to become saturated

What happens when a double bond is hydrogenated? What type of reaction is hydrogenation?

Energy is released in negative enthalpy change which can be measured and compared to different molecules - this makes it an exothermic reaction.

What shape is benzene?

Planar hexagonal

What is significant about the length of the C—C bonds in benzene?

They are intermediate in length between that of a single C-C and double C=C.

Why is benzene more stable cyclohexa-1,3,5-triene?

Due to the rings of delocalised electrons

Cyclohexa-1,3,5-triene is named what?

Kekulé's structure

What reactions should Kekulé's structure undergo? (Like alkenes do?)

Addition reactions

In reality reactions does benzene undergo?

Substitution reactions