Chemical Bonding and Molecular Structure - Result Question 21
####21. The boiling point of
[1994]
(a)
(b) intramolecular hydrogen bonding exists in p-nitrophenol
(c) there is intermolecular hydrogen bonding in
(d) p-nitrophenol has a higher molecular weight than
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Solution:
- (c) The b.p. of
-nitrophenol is higher than that of -nitrophenol because in -nitrophenol there is intermolecular -bonding but in -nitrophenol it is intramolecular H-bonding. Intramolecular Hydrogen bonding in -nitrophenol is a interaction with in the molecule whereas the intermolecular -bonding in -nitrophenol is a interaction between the molecules which results into higher boiling point. Intermolecular hydrogen bonding also results in a stronger driving force for cystal formation in other molecules generating higher melting temperature e.g. p-hydroxy benzoic acid.