What is the major product of the reaction?

• A.
• B.
• C.
• D.

Answer: (B)

Verified step by step guidance

1. Identify the type of reaction: The reaction involves an alkyl halide (2-chlorobutane) and a strong base (sodium ethoxide, NaOEt). This suggests an elimination reaction, likely E2, due to the strong base and secondary alkyl halide.
2. Determine the mechanism: In an E2 reaction, the base abstracts a proton from a β-carbon, and the leaving group (Cl) departs simultaneously, forming a double bond.
3. Identify possible β-hydrogens: In 2-chlorobutane, there are β-hydrogens on both the methyl and ethyl groups adjacent to the carbon bearing the chlorine.
4. Consider Zaitsev's rule: The major product in an elimination reaction is usually the more substituted alkene. Therefore, the base will likely abstract a hydrogen from the β-carbon that leads to the more substituted alkene.
5. Draw the major product: Removing a hydrogen from the β-carbon on the ethyl group will result in the formation of 2-butene, which is more substituted than 1-butene, making it the major product.