Formation of 2-butene as major product by dehydration of 2-butanol is according to
Markownikoff rule
Saytzeff rule
Peroxide effect
Anti-Markownikoff rule
CH3−CH−CH2−CH3→CH3−CH=CH−CH3 | 2−Butene OH 2−Butanol
According to this rule H atom goes from that β - carbon which is less hydrogenated.