Final answer:
The correct answer is D) C2H6 is the reducing agent, as it is oxidized in the combustion reaction, going from an oxidation state of -3 to +4.
Step-by-step explanation:
The correct answer is D) C2H6 is the reducing agent. In the given reaction, C2H6 (ethane) combines with oxygen (O2) to form carbon dioxide (CO2) and water (H2O). This is a combustion reaction, which is also a type of redox reaction, where ethane gets oxidized and oxygen gets reduced. The oxidizing agent is the species that accepts electrons, which is oxygen in this case, and the reducing agent is the species that donates electrons, which is ethane (C2H6).
During the reaction, carbon is oxidized from an oxidation state of -3 in ethane (each hydrogen contributes -1 and there are 6 hydrogens) to +4 in carbon dioxide. Thus, ethane is the compound that contains the element being oxidized, making it the reducing agent.