Q. (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

A) $I < II < III < IV$
B) $I < II < IV < III$
C) $IV < I < II < III$
D) $IV < II < I < III$
Explanation

(c)
1, 4-dihydroxy benzene shows the highest boiling point among given compounds because it forms strong intermolecular hydrogen bonds (It does not form intermolecular H-bonding.)
[image:4_image131.emf]
Order of H-bonding in $o$, $m$ and $p$-isomers of a compound is given below
Intermolecular H-bonding, $o < m < p$-isomers
intermolecular H-bonding
$o > m > p$ isomers.
Hydroxy benzene do not form a chain of H-bonding . Hence, intermolecular H-bond is stronger than intermolecular H-bonds, so the stability of 1, 4-dihydroxy benzene is highest. Hence its boiling point is highest. The increasing order of the boiling points of the given compound is
$IV < I < II < III$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

Want more practice?
Practice Chemical Bonding and Molecular Structure MCQs