Under standard conditions, the spontaneous reaction in a voltaic cell i S₂U³⁺ + Cd²⁺→2 U⁴⁺ + Cd (s) . Consider the three statements below and choose the correct answer.
I. The cadmium is the positive electrode in the cell.
II. A salt bridge is necessary in this cell.
III. The U³⁺ is oxidized in the cell.

Question

Quizplus · Accepted Answer

The reaction described involves a voltaic cell where U^3+ is being reduced to U^4+ (gaining an electron), and Cd is being oxidized to Cd^2+ (losing electrons). This means that cadmium is the negative electrode (anode) where oxidation occurs, not the positive one. A salt bridge is indeed necessary for maintaining electrical neutrality by allowing ions to flow between the two half-cells. Lastly, U^3+ is being oxidized to U^4+, not reduced, making statement III incorrect as it implies the opposite. However, the correct interpretation of the reaction shows that U^3+ is actually reduced, indicating a mistake in my explanation of statement III. Given the nature of voltaic cells, all statements are intended to be true based on the correct understanding of the cell's operation, including the necessity of a salt bridge and the roles of oxidation and reduction.

Under Standard Conditions, the Spontaneous Reaction in a Voltaic Cell