With a small electron-donating group on the ring, it is possible to get as much as a 2:1 ratio of ortho to para. Why might this be?

Electrophilic Aromatic Substitution is a reaction where an electrophile replaces a hydrogen atom on an aromatic ring. In the presence of a catalyst like FeCl3, chlorine acts as the electrophile, attacking the benzene ring. The position of substitution is influenced by existing substituents on the ring, which can direct the incoming group to ortho, meta, or para positions.

Ortho/para directing groups are substituents on an aromatic ring that increase the electron density at the ortho and para positions, making them more reactive to electrophilic attack. Electron-donating groups, such as alkyl groups, stabilize the carbocation intermediate formed during EAS, favoring substitution at these positions. This explains the higher ratio of ortho to para products in the presence of such groups.

Steric and electronic effects influence the distribution of substitution products in EAS. Small electron-donating groups, like methyl, enhance electron density at ortho and para positions, but steric hindrance is less at the para position. However, the ortho position can still be favored due to proximity effects and resonance stabilization, leading to a 2:1 ortho to para product ratio.