Final answer:
In the reaction 2K(s) + Cu(C₂H₂O₂)₂(aq) → 2KC₂H₃O₂(aq) + Cu(s), the reducing agent is potassium (K), as it loses electrons (oxidation) and enables the reduction of another substance.
Step-by-step explanation:
The question is asking to determine the reducing agent in a given chemical reaction between potassium (K) and copper(II) acetate (Cu(C2H2O2)2). In any redox reaction, the reducing agent is the substance that donates electrons to another substance, thereby reducing it. In this case, potassium (K) starts as a solid metal and ends up as part of the compound K(C2H3O2) in aqueous solution. This means that the potassium atoms have lost electrons (oxidation) and, therefore, are the reducing agent because they have enabled the reduction of another substance, which in this case is copper(II) acetate.
Through this process, the potassium atoms act as the electron donor, and in the process of donating electrons, potassium is oxidized, and thus it is the reducing agent. Given this information, the answer to the question is E) K, as this is the species that loses electrons and facilitates the reduction of another species. This is supported by knowledge of redox chemistry, where the reducing agent undergoes oxidation to reduce another substance.