How to find the major product of acid catalysed dehydration of unsymmetric alcohols. For example, in the dehydration of butan-2-ol using conc. H2SO4, which is the major product? But-1-ene or But-2-ene? And, in the dehydration of 1-methylcyclohexanol, the major product is 1-methylcyclohexene and not methylenecyclohexane. But how did we work it out??
Zaitsev's rule clearly addresses your query. Or you could look at it this way. The product with more hyper-conjugation is more stable. Hence but-2-ene is more stable than but-1-ene. Always see hyper-conjugation for more stable, major product.