Question

What is tautomerism?. explain giving examples..!!!

Answer 1

A reaction which involves simple proton transfer in an intramolecular fashion is called a tautomerism. Keto-enol tautomerism is a very common process, and is acid or base catalysed. Typically the 'keto' form of the compound is more stable, but in some instances the 'enol' form can be the more stable.

Answer 2

Tautomerism :- it is a special kind of isomerism, where two structural isomer exist in dynamics equilibrium .

example :-

CH3— CO —CH3 <=> CH3—COH=CH2

it arise due to the movement of any ion between two polyvalent atoms , so , IR is also called IONOTRPPY .
it is also known as :-
# KRYPTOMERISM
#ALLEOTROPISM
#MEROTROP Y
#PUEDOMERISM .

there are Various type of tautomerism

→ keto- enol tautomerism
→Nitro- acinitro " "
→Nitroso- oximino " "
→Amino- imino " " "
→ Lactam- lactim " "
→ Cyno- isocyno " "

but Keto -enol tautomerism are special one .

keto - enol tautomerism :-
the tautomerism is exist in which keto form and enol form exist in equilibrium is called keto- enol tautomerism .

Keto form :- contains a potential -CO- ( carbonyl) group , { means when carbonyl group directly touched C-atom or H-atom then we ask that is Keto form }
example :-

-CO —O—H ( this is not keto form becoz
-CO—H { this is a Keto form

enol form :- ene + ol

>C=C< + —OH

example :- H, H >C = C < OH , H is an enol form

===================================
condition of keto - enol tautomerism :-
==================================
1) All enol form can show keto -enol tautomerism.

2) the keto form must have a tautomerisable H- bond

alpha -H is known as tautomerisable H-atom

example :-

H—C = C —CO , here left side H is a T-H atom .