Write the half-reaction that occurs at a hydrogen electrode in acidic aqueous solution when it serves as the cathode of a voltaic cell. Express your answer as an ionic half-reaction. Identify all of the phases in your answer. nothing A chemical reaction does not occur for this question. Request Answer Part B Write the half-reaction that occurs at a hydrogen electrode in acidic aqueous solution when it serves as the anode of a voltaic cell. Express your answer as an ionic half-reaction. Identify all of the phases in your answer. nothing A chemical reaction does not occur for this question.