Step 1: Understanding the Question:
The reaction involves an alkyl halide and alcoholic potassium hydroxide, which is a condition for dehydrohalogenation (elimination).
Step 2: Key Formula or Approach:
Saytzeff's Rule: In a dehydrohalogenation reaction, the preferred (major) product is the alkene that has the greater number of alkyl groups attached to the doubly bonded carbon atoms (the more substituted alkene).
Step 3: Detailed Explanation:
1. Reaction Type: \(\beta\)-elimination.
2. Structure Analysis: 2-bromopentane has \(\beta\)-hydrogens on Carbon-1 and Carbon-3.
- Removing H from C-1 gives Pent-1-ene (monosubstituted).
- Removing H from C-3 gives Pent-2-ene (disubstituted).
3. Selection: Pent-2-ene is more stable and more substituted.
According to Saytzeff's rule, Pent-2-ene is the major product.
Step 4: Final Answer:
The major product of the reaction is Pent-2-ene.