Keto-enol tautomerism is an equilibrium process that involves the interconversion between a carbonyl compound keto form and an enol an alcohol with a double bond . In the case of cyclohexanone, the keto-enol tautomerism can be described as follows:1. Keto form: Cyclohexanone2. Enol form: CyclohexenolHere is the complete mechanism for the keto-enol tautomerism of cyclohexanone:Step 1: Protonation of the carbonyl oxygenA proton from an acid catalyst usually a weak acid like water or an alcohol protonates the carbonyl oxygen of cyclohexanone, making it a better leaving group. This forms an oxonium ion intermediate.Cyclohexanone + H [Cyclohexanone-OH]Step 2: Formation of the enol intermediateA neighboring carbon-hydrogen bond -hydrogen breaks, and the electrons from this bond form a double bond with the carbonyl carbon. Simultaneously, the oxygen with the positive charge oxonium ion loses a proton, forming the enol form of cyclohexanone, called cyclohexenol.[Cyclohexanone-OH] Cyclohexenol + HThe transition state involved in this process is a high-energy state where the -hydrogen is partially bonded to both the -carbon and the carbonyl carbon, while the carbonyl oxygen is partially bonded to the hydrogen ion.The reverse process enol to keto follows the same mechanism but in the opposite direction:Step 1: Protonation of the enol oxygenCyclohexenol + H [Cyclohexenol-OH]Step 2: Formation of the keto formThe double bond between the -carbon and carbonyl carbon breaks, and the electrons from this bond form a new bond with the protonated oxygen. Simultaneously, a new -hydrogen bond is formed, resulting in the keto form, cyclohexanone.[Cyclohexenol-OH] Cyclohexanone + HThe equilibrium between the keto and enol forms depends on the specific compound and reaction conditions. In most cases, the keto form is more stable and predominant at equilibrium.