hydrogen bond and its types

Hydrogen bonds can be classified into two types; Intermolecular hydrogen bond and Intramolecular hydrogen bond.

Intermolecular hydrogen bond

This occurs when the hydrogen bonding is between H-atom of one molecule and an atom of the electronegative element of another molecule. For example (i) hydrogen bond between the molecules of hydrogen fluoride. (ii) hydrogen bond in alcohol or water molecules.

Intermolecular hydrogen bond results into association of molecules. Hence, it usually increases the melting point, boiling point, viscosity, surface tension, solubility, etc.

illustration of Intermolecular hydrogen bond

Intramolecular hydrogen bond

This bond is formed between the hydrogen atom and an atom of the electronegative element (F,O,N) , of the same molecule .

Intramolecular hydrogen bond results in the cyclization of the molecules and prevents their association. Consequently, the effect of this bond on the physical properties is negligible. For example, intramolecular hydrogen bonds are present in molecules such as

o-nitrophenol, o-nitrobenzoic acid, etc.

structure of o-nitrophenol showing intramolecular hydrogen bonds

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