Ortho and Para nitrophenols can be separated by steam distillation. This is because
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → o-nitrophenol undergoes intramolecular hydrogen bonding
Steam distillation separates a compound that is volatile in steam from one that is not. The volatility of the nitrophenols depends on the kind of hydrogen bonding they form.
o-Nitrophenol, held by intramolecular hydrogen bonding, is the volatile isomer and distils over with steam; p-nitrophenol, associated by intermolecular hydrogen bonds, stays behind.
Why the other options are incorrect
Option (2) p-nitrophenol undergoes intramolecular hydrogen bonding — Incorrect. In the para isomer the groups are too far apart to bond within one molecule; its hydrogen bonding is intermolecular.
Option (3) o-nitrophenol undergoes intermolecular hydrogen bonding — Incorrect. The ortho isomer bonds within the molecule; intermolecular bonding is what makes the para isomer less volatile.
Option (4) o-nitrophenol is water soluble — Incorrect. Because its –OH is tied up internally, o-nitrophenol forms few hydrogen bonds with water and is only sparingly soluble; the separation depends on volatility, not solubility.
NCERT (2026-27 edition):
Electrophilic Aromatic Substitution – …
