Why is the nitro group a meta director?

Answer 1

nitro group is very electronegative,so it withdraws electron from the benzene ring so as to destabalize the carbocations in the ortho- and para- position.

Nitro group is also fairly bulky so steric hinderance limits the formation of ortho product.ok?

Answer 2

The oxygens attached to the nitrogen are more electronegative and are electron hogs. This effect causes a partial charge on the oxygen. Adding to the ring in the ortho or para fashion would create a molecule with a resonance structure that placed a positive charge on the nitro carbon. This means two adjacent carbons would have positive charges - which is undesirable. Adding in the meta fashion however, the intermediate does not place a positive charge on the nitro carbon. Adding meta has more valid resonance structures in this case, so the nitro group is a deactivating meta director. However, nitrogen groups are not always meta directors. NH2 for example causes nitrogen to have a partial negative charge and is therefore an activating ortho/para director. So, be careful with nitrogen groups. Also note, that Friedel Crafts chemistry does not work with nitrogen groups, that act as meta directors.

Answer 3

Draw Benzoic Acid. Once you've drawn it look at the carboxylic acid functional group. You'll notice that the O and OH being more electrophilic would inductivley move electron density away from the carbon and the benzene ring. Electron withdrawing groups draw charge in such a way that the positive charge on the bezene ring moves to every position but the meta position.

In the case of an Electron donating group the negative charge donated by the group moves in such a way to land on the meta and para positions meaning they have more electron density then the meta position allowing a reaction to more readily occur.

Answer 4

this is because the nitro group on the benzene ring is electron withdrawing and hence it directs incoming group towards meta position .