Question

An active (metal) electrode was found to lose mass as the oxidation-reduction reaction was allowed to proceed. Was the electrode part of the anode or cathode? Explain.

Short answer

The active electrode that loses mass is the part of anode.

Step-by-step solution

Define oxidation and reduction

• Avoltaic or a galvaniccell is an electrochemical cell which derives the electrical energy from the spontaneous redox chemical reactions which occur inside the cell.
• A galvanic cell usually contains two different metals which are dipped in an electrolytic solution or of an individual half-cells having different metals and their ions present in the solution, joined by a salt-bridge or divided by a porous membrane.

Determine balanced reaction for each pair of half reactions in an acidic solution.  

Active electrodes are those electrodes in which the mass are found to be changes as the chemical reaction proceeds in the electrolyte solution.

When the electricity is pass through a solution of an electrolyte, chemical reaction occurs at the electrodes. The electrode connected to negative terminal of battery is termed as cathode whereas that connected to positive terminal of battery is termed as anode. At anode, oxidation of metal atoms takes place and they move into the solution. Therefor the active electrode that loses mass is the part of the anode.