Let's look at 2-bromobutane reacting with a base like ethoxide. Step 1: The base looks for a hydrogen on a carbon next to the one holding the Bromine. Step 2: There are two options—the CH3 at the end (carbon 1) or the CH2 in the middle (carbon 3). Step 3: Removing H from carbon 3 creates but-2-ene. Removing H from carbon 1 creates but-1-ene. Step 4: Saytzeff’s Rule says but-2-ene is the major product because it has two alkyl groups attached to the double bond, making it more stable than but-1-ene which only has one.