Final answer:
The substance that gives a dicarbonyl compound with ozone followed by reduction with zinc and water is benzene (C6H6), forming glyoxal. Therefore, the correct option is B.
Step-by-step explanation:
The student asked which among the following substances would give a dicarbonyl compound when treated with ozone followed by reduction with zinc and water: ethane (C₂H₆), benzene (C₆H₆), acetylene (C₂H₂), or both benzene and acetylene.
The correct answer is benzene (C₆H₆). When benzene is treated with ozone (a process known as ozonolysis), followed by reduction with zinc and water, it forms a glyoxal, which is a dicarbonyl compound. Ethane would not react with ozone in this manner, and acetylene would form a single carbonyl compound, not a dicarbonyl.