Effect Of Hydrogen Bonding
Chemical Bonding of Class 11
EFFECT OF HYDROGEN BONDING
Hydrogen bonding has got a very pronounced effect on certain properties of the molecules. As
State of the substance:
H2O exists in liquid state whereas H2S in gaseous state because hydrogen bonding exist in water and no H-bonding exists in H2S.
Solubility:
The organic compounds like alkane, alkenes, alkynes are insoluble in water due to absence of H-bonding whereas alcohols, organic acids, amines are soluble in water due to H-bonding.
Boiling point:
High boiling and melting points of NH3 ,H2O and HI in comparison to hydrides of other elements of V, VI and VII groups to which N, O and F belong respectively are due to hydrogen bonding.
Acidity of different isomers:
Strength of certain acids and bases can be explained on the basis of hydrogen bonding eg. when we compare the acidic strength of o – m – and p – hydroxyl benzoic acid.
The abnormally high dissociation constant of o – hydroxybenzoic acid is due to the fact that the conjugate base is stabilised by hydrogen bonding.
These can be evident from the following examples.
