Correct Answer - A
In `o-nitrophenol`, because chelation (intramolecular hydrogen bonding) is possible, hydrogen bonding with the solvent water molecules is hindered and hence, solubility is lowered. Moreover, since chelation causes the `o-compound` to behave as a monomer, this isomer will be more volatile than the corresponding `m-` and `p-isomers`.
Thus, the effects of chelation are lower solubility and greater volatility in the `o-nitrophenol`, thereby enabling it to be separated from its `m-` and `p-isomers` by steam distillation. Howerver, `o-isomer` may also be separated from the `p-isomer` by crystallization or by chromatography.
