Question

The boiling point of p-nitrophenol is higher than
that of o-nitrophenol because
(a) NO₂ group at p-position behave in a different
way from that at ????-position.
(b) intramolecular hydrogen bonding exists in p-nitrophenol
(c) there is intermolecular hydrogen bonding in p-nitrophenol
(d) p-nitrophenol has a higher molecular weight than o-nitrophenol.

Answer 1

The boiling point of p-nitrophenol is higher than that of o-nitrophenol because of intermolecular hydrogen bonding.

Explanation:

Let us understand the difference between p-nitrophenol and o-nitrophenol. Here in p-nitrophenol, we can say that molecular association is on account of presence of extensive hydrogen bonding.

This extensive hydrogen bonding is termed as the intermolecular hydrogen bonding. This is why it is considered to have a much higher boiling and melting point.  

Now in o-nitrophenol the NO2 and OH are considered to be in much closer proximity and so here when the proximity of closer the intramolecular bonding takes place.  

Thus here the correct answer is option C – there is intermolecular bonding existing in p-nitrophenol.