Consider the hydroxyl derivative of benzene given below
I. 1,2 - dihydroxy benzene
II. 1,3 - dihydroxy benzene
III. 1,4 - dihydroxy benzene
IV. Hydroxy benzene
The increasing order of boiling points of above mentioned alcohols is :
I < II < III < IV
I < II < IV < III
IV < I < II < III
IV < II < I < III
As we learnt,
All dihydroxy benzene will have higher boiling points than monohydroxy benzene. Also, among dihydroxy benzenes, 1,2 - dihydroxy benzene has the lowest boiling point due to intramolecular H - bonding.
Intramolecular H - bonding in 1,2 - dihydroxy benzene :
1, 4-dihydroxy benzene shows the highest boiling point among given compounds because it forms a strong intermolecular hydrogen bond (It does not form intramolecular H-bonding).
So, the increasing order of boiling points will be -
IV<I<II<III
Therefore, option(3) is correct.