Question

Complete the following statement for electrolysis of an aqueous salt solution:

When two half-reactions are possible at an electrode, the reduction with the (less/more) negative, meaning the (more/less) positive, electrode potential occurs.

Answer 1

In electrolysis of an aqueous salt solution, the reduction with the less negative electrode potential occurs. For example, in the electrolysis of aqueous sodium chloride, the reduction half-reaction at the cathode can involve either the electrolysis of water to produce hydrogen gas or the reduction of sodium ions to produce sodium metal.

Step-by-step explanation:

In electrolysis of an aqueous salt solution, when two half-reactions are possible at an electrode, the reduction with the less negative, meaning the more positive, electrode potential occurs.

For example, in the electrolysis of aqueous sodium chloride, the reduction half-reaction at the cathode can involve either the electrolysis of water to produce hydrogen gas or the reduction of sodium ions to produce sodium metal.

In general, the half-reaction with a higher electrode potential (less negative value) is preferred for reduction during electrolysis.