Question

Why does a concentration cell work?

Answer 1

A concentration cell is a type of a galvanic cell where the same type of a solution is used for the two compartments (cathode and anode) with the only difference is the concentration.

Explanation:

A concentration cell is a type of a galvanic cell where the same type of a solution is used for the two compartments (cathode and anode) with the only difference is the concentration.

A concentration cell is characterized by a standard cell potential equal to zero, since the oxidation half reaction and the reduction half reaction occurring at the anode and cathode respectively are the same.

Here is an example of a concentration cell.

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Where (a) is right after preparing the cell, and (b) is after the cell has operated enough time to discharge.

Note that at the beginning the concentration were different, and they become equal after discharge (equilibrium state).

Here is a video that explains the concentration cell in details:
Electrochemistry | The Concentration Cell.