Question

Why chlorine is ortho and para directing in chlorobenzene?

Answer 1

chloride is an activating group which decreases the e- density at ortho and para position through resonance putting +ve charge if you make resonating structures

as chloride is eletrophobic makes the benzene ring electropositive on ortho and para position through resonance

Answer 2

The answer is:

• The I effect of chlorine withdraws electrones from benzene ring.
• Hence tends to disstabalize the intermediate carbocation formed during the electrophillic substituion.
• so, cl donates it lone pair of electrons to the aromatic ring and hence increases the elctro density at the ortho and para positions.
• therefore in chlorobezene,reactivity is controlled by stronger stronger I effect while orientaion of incoming substituent is controlled by the weaker resonance effect.

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