According to Alexander Zaitsev the most preferred product for dehydrohalogenation of 2-Bromopentane will be:

Pent-2-ene

The correct answer is option 2. Pent-2-ene.

Zaitsev's Rule (or Saytzeff's Rule) is an empirical rule used in organic chemistry to predict the preferred product in an elimination reaction. According to this rule, during dehydrohalogenation (an elimination reaction where a hydrogen halide is removed), the most stable (and therefore the most substituted) alkene is typically the major product.

Dehydrohalogenation of 2-Bromopentane:

The reaction of 2-bromopentane with a strong base will lead to the elimination of HBr. According to Zaitsev's Rule, the more substituted alkene is favored.

According to Zaitsev's rule, pent-2-ene (option 2) is the preferred product because it is more substituted and, hence, more stable compared to pent-1-ene.