Order of Acidic Character of para, meta, ortho aminophenol and phenol:

Phenol (C6H5OH):
Phenol is an aromatic compound with a hydroxyl group (-OH) attached to a benzene ring. It is a weak acid due to the presence of the hydroxyl group which can donate a proton (H+) to a base. The acidity of phenol is influenced by the electron-donating or -withdrawing groups present on the benzene ring.

Aminophenol (C6H4NH2OH):
Aminophenol is a derivative of phenol in which an amino group (-NH2) is attached to the benzene ring. The presence of both the amino and hydroxyl groups makes aminophenol more acidic than phenol. The amino group is electron-donating, increasing the electron density on the oxygen atom of the hydroxyl group, making it easier to donate a proton.

Order of Acidic Character:
The order of acidic character among para, meta, and ortho aminophenol and phenol can be determined by considering the electron-donating or -withdrawing effects of the substituents on the benzene ring.

1. Ortho Aminophenol (C6H4(OH)(NH2)):
In ortho aminophenol, the amino group is in the ortho position (adjacent to the hydroxyl group). The presence of the amino group increases the electron density on the hydroxyl group, making it more acidic than phenol.

2. Para Aminophenol (C6H4(NH2)(OH)):
In para aminophenol, the amino group is in the para position (opposite to the hydroxyl group). The electron-donating effect of the amino group is slightly reduced compared to ortho aminophenol, resulting in a slightly lower acidity.

3. Meta Aminophenol (C6H4(NH2)(OH)):
In meta aminophenol, the amino group is in the meta position (two carbons away from the hydroxyl group). The electron-donating effect of the amino group is further reduced compared to ortho and para aminophenol. As a result, meta aminophenol is the least acidic among the three aminophenol isomers.

4. Phenol (C6H5OH):
Phenol is the least acidic compound among all. The absence of the amino group reduces the electron density on the hydroxyl group, making it less likely to donate a proton.

In summary, the order of acidic character is: Ortho Aminophenol > Para Aminophenol > Meta Aminophenol > Phenol. This is due to the different positions of the amino group relative to the hydroxyl group and the resulting electron-donating effects on the hydroxyl group.

As acidity is inversely proportional to pka value , the order is - ortho aminophenol(9.71)more acidic than meta aminophenol(9.87) than phenol (10) than para aminophenol(10.3). .... I think