When an electric current is passed through a conducting solution, some chemical reaction takes place. The changes observed because of this chemical reaction are called the Chemical effects of currents.
In general, the following three changes are observed:
Bubbles are Liberated at the Electrodes
This indicates that due to electric current, a gas is released.
Colour of the Solution Changes
Many solutions undergo a colour change when an electric current is passed through them.
There is a Deposition of Metal on the Electrodes
This is the most common and useful chemical change that occurs.
Let us understand this change with the help of copper sulphate solution and two electrodes, one made up of graphite and the other of copper. The graphite electrode is connected to the battery’s negative terminal and the copper electrode to the positive terminal. This makes the graphite a cathode and the copper an anode.
When the electric current is passed through the solution, it dissociates the copper sulphate into positively charged copper and negatively charged sulphate. The positively charged copper gets attracted to the negative electrode and gets deposited on its surface. With this, the copper in the solution gets exhausted. To overcome this loss, copper from the anode gets dissolved in the solution and the anode gets thinner.
This process of metal deposition is referred to as Electroplating. It is usually done to prevent corrosion. We will learn more about it in the next segment.
Summary
| Three chemical effects are observed due to the passing of electric current through liquids |
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