(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 the above-mentioned alcohols is:

Options

A. `I ltII ltIV ltIII`
B. `I ltII ltIIIlt IV`
C. `IVlt IIlt I lt III`
D. `IVlt I lt IIlt III`

Answer

D

Explanation

Among the given compounds, hydroxybenzene `(IV)` has least molar mass and therefore possess least boiling point. Among the three isomertic dihydroxybenzenes. `1,2`-dihydroxybenzene `(I)` froms intramolecular `H`-bonding with the result that it will not from intermolecular `H`-bonding leading to lowest boiling point. on the other hand `1, 3`-dihydroxybenzene `(II)` and `1,4`-dihydroxybenzene `(III)` does not undergo clelation, hence they will involve extensive intermolecular `H`-bonding leaching to higher boiling point. further intermolecular hydrogen bonding is stronger in the `p`-isomer than the `m`-isomer hence former has highest `b.p`. thus the decreasing order of boiling points is `IIIgt IIgt Igt IV`.