OC Destroyer problem #17 tautomers & constitutional isomerism

[Bobby Fischer]

The answer states, "This pair represents tautomers, which are simply constitutional isomers that co-exist in rapid equilibrium..."

Wait, whaa?? I thought to be a constitutional isomer that you need to have the same molecular formula (just different connectivity)?

Sure, tautomers are the keto and enol forms but the enol form has a Hydrogen atom that the keto does not.

How can the keto and enol forms be consitutional isomers?

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[Kingsta2426]

The answer states, "This pair represents tautomers, which are simply constitutional isomers that co-exist in rapid equilibrium..."

Wait, whaa?? I thought to be a constitutional isomer that you need to have the same molecular formula (just different connectivity)?

Sure, tautomers are the keto and enol forms but the enol form has a Hydrogen atom that the keto does not.

How can the keto and enol forms be consitutional isomers?

Because they have the same chemical formula, I'm pretty sure all tautomers are constitutional isomers.

 

[joeeeey3]

draw out the structure of enol and keto forms and count the number of Hydrogen, Carbon and Oxygen. They are equal in numbers in both forms

 

[NewBee12]

They have the same molecular formula. Look up the definition. It's in every Orgo book.
Best of luck.

 

[Bobby Fischer]

I feel pretty stupid right about now guys and gals.

Sorry about that. Duh. Yeah, when I actually stop and think about it long enough to count up the hydrogens, totally the same molecular formula.

Thanks for the replies.

I never formally learned this nor did I stop until now to really think about it. Now I hope I get questioned about this on the exam.