Construction of an Electrochemical Cell

Let us use the redox reaction given below to explain the construction of an Electrochemical Cell.

Zn (Solid) + CuSO₄ (Aqueous)   ZnSO₄ (Aqueous) + Cu (Solid)

The ionic form of the reaction is:

Zn + Cu²⁺    Zn²⁺ + Cu

This reaction can be split into the following two half reactions.

1. Oxidation half reaction

Zn  Zn²⁺ + 2e^-

2. Reduction half reaction

Cu²⁺ + 2e^-  Cu

Electrochemical or Galvanic or Voltaic Cells

An Electrochemical Cell is a device used to convert chemical energy (produced in a redox reaction) into electrical energy.

Electrochemical Cells are also known as Galvanic or Voltaic Cells.

If we take a zinc rod and place it in a container filled with copper sulphate solution heat will be produced. This happens due a spontaneous redox reaction given below:

Zn(Solid) + CuSO₄(Aqueous)  ZnSO₄(Aqueous) + Cu (Solid) deposited

As the reaction would proceed the zinc rod would get eroded ,copper particles would get deposited and solution would becom warm

.

It would be useful to be able to convert this chemical energy to electrical energy instead of heat energy. This is done by an electrochemical cell.