Question

Assertion (A) : Ortho and para nitrophenols can be separated by steam distillation.
Reason (R) : Ortho nitrophenol exhibits intramolecular hydrogen bonding while para nitrophenol exists as associated molecules.

• A. Both A and R are true and R is correct explanation of A.
• B. Both A and R are true and R is not correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Answer 1

The correct option is A Both A and R are true and R is correct explanation of A.

Para-nitrophenol, on account of larger distance between the two groups (OH and $N{O}_2$) does not show any intramolecular hydrogen bonding.

As result of intermolecular hydrogen bonding, the para derivative undergoes association, resulting in an increase in boiling point.

The ortho derivative is more volatile in steam, the para nitrophenol is completely non- volatile. They can be separated by steam distillation.

Option A is correct.