Q.Cyclohexylmethanol (cyclohexyl-CH2-OH) on treatment with conc. H2SO4 predominantly gives

Step 1. Protonation and loss of water from cyclohexyl-CH2-OH would first generate a PRIMARY carbocation on the exocyclic CH2 -- extremely unstable and never actually formed as such.

Step 2. A 1,2-hydride shift from the adjacent ring carbon into that cationic centre converts the primary cation into a SECONDARY carbocation sitting ON THE RING (at the carbon now bearing a methyl group, since the exocyclic carbon has become CH3 after accepting the hydride). …

Recognise that a primary carbocation adjacent to a ring will rearrange via hydride shift to a more stable ring carbocation, then apply Saytzeff's ru …

• Assuming a primary alcohol always dehydrates by simple E2 without checking whether a rearrangement to a more stable carbocation is available -- here the adjacent ring carbon offers exactly that escape route via a hydride shift. …