The Wagner-Meerwein rearrangement is a 1,2-rearrangement of a carbocation that involves the migration of an alkyl or aryl group, or a hydrogen atom, to an adjacent carbocation center. In the case of cyclohexanol to cyclohexene, the mechanism involves the following steps:1. Protonation of the alcohol: The reaction starts with the protonation of the hydroxyl group OH of cyclohexanol by a strong acid, such as sulfuric acid H2SO4 or phosphoric acid H3PO4 . This step generates a good leaving group, water H2O , and a carbocation on the carbon atom that was previously bonded to the hydroxyl group.Cyclohexanol + H2SO4 Cyclohexyl oxonium ion + H2O2. Formation of the initial carbocation: The water molecule leaves, resulting in the formation of a secondary carbocation at the position where the hydroxyl group was initially attached.Cyclohexyl oxonium ion Secondary carbocation + H2O3. Hydride shift 1,2-rearrangement : A hydride H- from the adjacent carbon atom migrates to the carbocation center, leading to a more stable tertiary carbocation. This step is the key step in the Wagner-Meerwein rearrangement.Secondary carbocation Tertiary carbocation via hydride shift 4. Deprotonation and formation of cyclohexene: Finally, a base such as the bisulfate ion, HSO4- deprotonates a hydrogen atom from the carbon adjacent to the carbocation center, resulting in the formation of a double bond C=C and the desired product, cyclohexene.Tertiary carbocation + HSO4- Cyclohexene + H2SO4In summary, the Wagner-Meerwein rearrangement of cyclohexanol to cyclohexene involves the protonation of the alcohol, formation of a secondary carbocation, a hydride shift to form a more stable tertiary carbocation, and deprotonation to generate the final product, cyclohexene.