Think about Ketone - Enol tautomer....Ketone has C=O and Enol has C=C with oxygen having a proton and single bond with C, when u see such arrangement, there is a possibilty of tautomeric shift.
This is how i recognize a tautomeric shift. When you see HGSO4 and triple bond add the OH to the more subsituted carbon in the triple bond. Afterwards know that you need to from the carbonyl from the OH group which results in rearrangement. Hope this helps dude
When you see enol form, usually tautomerizes to it's keto form. Keto form (C=O) is usually more stable due to the fact that the double bond (electrons) are arranged to most eletronegative atom which in this case is Oxygen (Oxygen vs Carbon in electronegativity, e- would prefer to be with O).
One of the exception that enol form would be prefered is if you have phenol, you could make it to its keto form, but remember phenol (enol form) is aromatic and it's keto form becomes non aromatic. Aromatic compounds are more stable thant non aromatic. Due to this case of phenol, would prefer to stay its enol form.
Hope that helps @.@
