5. Benzene and cyclohexene have different reactivity towards addition reaction. i. Explain why do benzene and cyclohexene undergo different type of reaction with bromine.

Question

5. Benzene and cyclohexene have different reactivity towards addition reaction. i. Explain why do benzene and cyclohexene undergo different type of reaction with bromine. ii. State the type of reaction for both compounds. iii. Write the chemical reaction equations of benzene and cyclohexene in (i). (

Answer 1

Hi Mosho,

The key concept to answer this question lies in the stability of molecules. Stability is also related inversely to reactivity. Basically, the more stable a molecule is, the "happier" it is, and thus the less reactive it will be in reactions.

Comparing two molecules in an addition reaction (whether it is nucleophilic addition or electrophilic addition) made a lot easier if we start to think about each molecule's reactivity, and thus each molecule's stability.

Let's take cyclohexene vs benzene. Though they are similar in molecular formula, note that benzene is SUPER stabilized by it's aromaticity (conjugation of p-orbitals, allowing for massive electron delocalization). Since benzene is so much more stable than cyclohexene, benzene is much less reactive than cyclohexene.