$- NO _{2}$ group at o- and $p-$ position withdraws electrons of the $O - H$ bond towards itself by the stronger $-R$ effect while the $- NO _{2}$ group at $m$-position with draws electrons of the $O - H$ bcnd by the weaker -I effect. Thus, $o$ - and $p$ - nitrophenols are more acidic than $m$ - nitrophenol. Among $o$- and $p$ nitrophenols, o- nitrophenol is little less acidic than $p$-nitrophenol due to intramolecular H-bonding which makes loss of a proton little more difficult.
$\therefore $ The order of acidity of nitrophenols is $p$- nitrophenol > $o$- nitrophenol > $m$- nitrophenol
Phenol is a different class of organic compounds that are usually found in wide usage in an extensive range of industries and also for domestic purposes. Phenol is formed when a hydrogen atom in a benzene molecule is replaced by the chemical -OH group.
Phenol is also called as Carbolic acid. It is an aromatic organic compound having the molecular formula C6H5OH. It is a volatile white crystalline solid. The molecule consists of a phenyl group (−C6H5) bonded to a hydroxy group (−OH). Phenol is mildly acidic, it requires careful handling because it can cause chemical burns.
Classification of Phenol
On the basis of the different number of hydroxyl groups attached, the phenols can be classified further into three types.
Monohydric phenols: These contain one -OH group.
Dihydric phenols: These contain two -OH groups. These may be ortho-, meta- or para- derivative.
Trihydric phenols: These contain three -OH groups.
Properties of Phenol
Phenol is an organic compound that is appreciably soluble in water, with about 84.2 g dissolving in 1000 mL (0.895 M).
It is a weak acid.
is highly reactive toward electrophilic aromatic substitution.
