Concept:Acid-catalysed dehydration of an alcohol proceeds through carbocation formation and possible rearrangement to give the more stable alkene.Explanation:The given alcohol is 3,3-dimethyl-2-butanol: CH3​−C(CH3​)2​−CH(OH)−CH3​.In presence of H2​SO4​, the −OH group is protonated to form −OH2+​, which leaves as water.CH3​−C(CH3​)2​−CH(OH)−CH3​+H+→CH3​−C(CH3​)2​−CH(OH2+​)−CH3​Loss of water gives a secondary carbocation:CH3​−C(CH3​)2​−CH+−CH3​+H2​OThis secondary carbocation rearranges by a 1,2-methyl shift to form a more stable tertiary carbocation:CH3​−C(CH3​)2​−CH+−CH3​1,2-methyl shift​CH3​−C+(CH3​)−CH(CH3​)−CH3​Finally, loss of a proton from an adjacent carbon gives the more substituted alkene according to Saytzeff’s rule:CH3​−C+(CH3​)−CH(CH3​)−CH3​→CH3​−C(CH3​)=C(CH3​)−CH3​+H+Answer:The product X is 2,3-dimethyl-2-butene.Correct option: A.
