Final answer:
The product formed when an alkene is treated with H₂ and a Pd catalyst is an alkane. This reaction is called hydrogenation.
Step-by-step explanation:
The product formed when an alkene is treated with H₂ and a Pd catalyst is an alkane (option B). This reaction is known as hydrogenation, where hydrogen atoms are added to the carbon-carbon double bond in the alkene, resulting in the formation of a single bond and the conversion of the alkene to an alkane. The Pd catalyst helps facilitate the reaction.