The most suitable method of separation of a mixture of ortho and para nitrophenol in the ratio `1:1` is :

Options

A. sublimation
B. chromatography
C. crystallisation
D. steam distillation

Answer

D

Explanation

Steam distillation is used to purify the substances which
(i) are volatile in steam but are immiscible with water .
(ii) posses sufficiently high vapour pressure at the boiling point of water .
(iii) contain non-volatile impurities .
The process of steam distillation can also be used to separate a mixture of two organic compounds one of which is steam volatile while the other is not .
In ortho and para-nitrophenol , artho-nitrophenol has intramolecular H-bonding . So , it has lower boiling point . Intermolecular H-Bonding more strong then intramolecular H-bonding . Whereas para-nitrophenol has intermolecular H-bonding . So , it has higher boiling point . Due to difference in boiling points ortho and para-nitrophenol can be separated from each other by distillation .