Final answer:
The compound A is identified as 4-methyl-1-pentene due to its reaction products upon hydrogenation and ozonolysis, which are consistent with the structural features of this compound.
Step-by-step explanation:
The student is asked to identify an organic compound A with the formula C₅H₈ that on hydrogenation yields compound B with the formula C₅H₌₁₂. Furthermore, compound A produces methanal and 2-ketopropanal upon ozonolysis. Based on this information and the given molecular formulae, we can determine that compound A has a double bond, as indicated by the fact that it is an unsaturated hydrocarbon converting into a saturated one upon hydrogenation.
Moreover, the ozonolysis products indicate that the double bond is located at the end of an alkyl chain since methanal (formaldehyde) is formed, which implies the cleavage of a formyl group (H-C=O). The other product, 2-ketopropanal, demonstrates the presence of a ketone functional group within a three-carbon chain. Considering the number of carbons and the type of products obtained from ozonolysis, the best match among the given options is compound (d), which is 4-methyl-1-pentene. This compound possesses the necessary structural features — a terminal double bond that upon ozonolysis will yield methanal and 2-ketopropanal.