In which compound enol form is more stable than its keto form?

Compound (C) forms phenol which is much more stable than keto form because of great stability associated with aromatic ring which is absent in keto form.

Why enol form of Ethylacetoacetate is more stable than keto form?

The enol form of ethylacetoacetate is stabilized by intramolecular hydrogen bonding. It is a six membered chelate ring which adds up to its stability. For this reason, enol form of ethylacetoacetate is more stable than the keto form.

Why is keto form favored?

Despite being a reversible reaction, the keto form is more stable and thus favored by equilibrium. This is because carbon double bound to oxygen is more stable than a carbon single bound to oxygen and single bound to hydrogen. Therefore, the enol form of this molecule will predominate at equilibrium.

Why phenol is unstable in keto form?

Answer: In the case of phenol, the keto form results in the loss of the delocalized aromatic system, and this form is higher in energy (less stable) than the enol form which is lower in energy due to the delocalization of the electrons in the aromatic system. so phenol is more stable than its keto form.

Why does polar protic solvent decrease enol?

This is because in a polar solvent, the lone pairs will be already involved in hydrogen bonding with the solvent, making them less available to hydrogen bond with the enol form and thus taking away from the stability of the enol form.

Why enol form is more stable than keto form for phenol acetaldehyde?

The reason for the equilibrium lying to the left is due to bond energies. The keto form has a C–H, C–C, and C=O. bond whereas the enol has a C=C, C–O an O–H bond. The keto form is therefore more thermodynamically stable by 12 kcal/mol (48 kJ/mol).

Which enolate resonance form is more stable and why?

Of the two resonance structures of the enolate ion the one which places the negative charge on the oxygen is the most stable. This is because the negative change will be better stabilized by the greater electronegativity of the oxygen.

Why does ethyl acetoacetate show tautomerism?

They are loosely bound to the molecule. Those methylene hydrogens are moved towards those functional groups and exhibit an isomerism is called keto-enol tautomerism. The representation of keto-enol tautomerism in ethyl acetoacetate is as follows. So, ethyl acetoacetate exhibits keto-enol tautomerism.

What is the major factor which stabilize the Enolic variety of acetoacetic ester?

It is a weak acid (like most alkyl carboxylic acids), with a pKa of 3.58. Acetoacetic acid displays keto-enol tautomerisation, with the enol form being partially stabilised by extended conjugation and intramolecular H-bonding.

Is keto or enol more polar?

The implicit or explicitly stated rationale for this observation in molecules such as acetylacetone is that the keto form is more polar than the enol form and hence is more stable in polar solvents (2, 3, 7–10).