(a) Write the half-reaction that occurs at an oxygen electrode in acidic aqueous solution when it serves as the cathode of a voltaic cell. (b) Write the half-reaction that occurs at an oxygen electrode in acidic aqueous solution when it serves as the anode of a voltaic cell. (c) What is standard about the standard oxygen electrode?

(a) When an oxygen electrode serves as the cathode in a voltaic cell in acidic aqueous solution, the reduction half-reaction is: \(O2(g) + 4H^{+}(aq) + 4e^- \rightarrow 2H2O(l)\) (b) When an oxygen electrode serves as the anode in a voltaic cell in acidic aqueous solution, the oxidation half-reaction is: \(2H2O(l) \rightarrow O2(g) + 4H^{+}(aq) + 4e^-\) (c) The standard oxygen electrode, also called the standard hydrogen electrode, is a reference electrode used in electrochemistry under standard conditions (25°C, 1 atm for gases, and 1M concentration for other species). It has a reduction potential of 0 volts and is used to determine the standard electrode potential values of other electrodes in comparison.