Suppose that each of the following pairs of redox couples is combined to form a galvanic cell that generates a current under standard conditions. Identify the oxidizing agent and the reducing agent, write a cell diagram, and calculate the standard cell potential from the standard potentials of the electrodes.

(a) Pt²⁺/Pt and AgF/Ag,F^–; 

(b) Cr³⁺/Cr²⁺ and I₃^–/ I^–; 

(c) H⁺/H^– and Ni²⁺/Ni;

(d) O₃/O₂,OH^– and O₃,H⁺/O^–.