Q. Tautomerism is the phenomenon in which two structural isomers differing in the relative positions of their atoms are spontaneously interconvertable and can exist in dynamic equilibrium. The two forms in tautomeric equilibrium are called tautomers of each other. The interconvertibility of tautomers is a chemical reaction which involves making and braking of bonds. Tautomers are true isomers, and either of the individual tautomeric forms may be isolated
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In the keto-enol tautomerism of dicarbonyl compounds the enol form is preferred in contrast to the keto form, this is due to

 96  142 Organic Chemistry – Some Basic Principles and Techniques Report Error

Solution:

Due to hydrogen bonding and resonance enol form is preferred in contrast