(c) A substituted benzene can undergo electrophilic aromatic substitution, discuss broadly the effect of a substituent on; Orientation ?

The orientation of a substituent on a benzene ring can greatly affect the outcome of electrophilic aromatic substitution reactions.

1. Ortho, Meta, Para directing: Substituents can be classified as ortho, meta, or para directing based on their effect on the orientation of incoming electrophiles. Ortho and para directing substituents direct the incoming electrophile to the ortho and para positions, respectively, while meta directing substituents direct the electrophile to the meta position. This is due to the electron-donating or electron-withdrawing nature of the substituent, which affects the distribution of electron density on the benzene ring.

2. Activating vs. Deactivating: Substituents can also be classified as activating or deactivating based on their ability to increase or decrease the reactivity of the benzene ring towards electrophilic substitution. Activating substituents, such as alkyl groups or electron-donating groups, increase the electron density on the benzene ring, making it more reactive towards electrophiles. Deactivating substituents, such as nitro groups or halogens, decrease the electron density on the benzene ring, making it less reactive towards electrophiles.

3. Steric effects: Substituents can also have steric effects on the orientation of electrophilic substitution reactions. Bulky substituents may hinder the approach of electrophiles to certain positions on the benzene ring, leading to selective substitution at other positions.

Overall, the orientation of a substituent on a benzene ring plays a crucial role in determining the regioselectivity and reactivity of electrophilic aromatic substitution reactions. By understanding the effects of different substituents on the benzene ring, chemists can predict and control the outcome of these reactions.