Consider the following reaction: 2Fe2+(aq) + Cu2+ --> 2Fe3+(aq) + Cu. When the ion concentrations change to the point where the reaction comes to equilibrium, what would be the cell voltage?

At equilibrium, the cell voltage is zero volts.

Explanation:

During an electrochemical reaction, electrical energy is produced. The reaction continues to produce electrical energy until a point is reached in which the reaction attains equilibrium.

Before the reaction attains equilibrium, the cell voltage continues to decrease progressively as the reaction progresses. At equilibrium, the cell voltage becomes zero and the read out voltmeter records 0 V.

Hence, at equilibrium, the cell voltage is zero volts.