1)Which one is a stronger acid- o- Toluic acid or p- Toluic acid?
2)Why is ortho nitro aniline less basic than para nitro aniline?
ans1) I think its p- Toluic acid because o- Toluic acid has more +I effect than p- Toluic acid. Correct if anything wrong
ans2) I know that it is due to ortho effect.
Now I don't understand how ortho effect will decrease its basicity.
Due to the steric repulsion, the lone pair on NH2- will not be in conjugation with the benzene ring. So partly its basicity is increased relative to aniline. Now there is a Hydrogen bond between NO2- and NH2- i.e. the oxygen of NO2 group tends to pull away the H of NH2- group.
Are the lone pair of electrons also pulled away due to Hydrogen bond? If no then what causes a decrease in its basicity?
Moreover, -I effect is more for ortho than para substituted aniline.
Please clear my doubt.
1061) do u mean o-toluic benzoic acid and p-toluic benzoic acid ??
If so, then it is o-toluic benzoic acid because of ortho effect
Remember : Ortho effect is an interplay between steric repulsion and the formation of H-bonds (if possible). . So both these factors have to be weighed when attributing something to ortho effect.
39http://www.chemicalforums.com/index.php?topic=42182.0
Check out the replies in this thread, reply number 4 onwards. It'll help you understand what the ortho effect really is, and it may answer some of your questions. "Ortho effect" is a broad term applied when unusual properties are observed in ortho substituted benzene molecules.
