Galvanic Cell

In our day to day life, we see a lot of examples where we use cells

The hand watch we use runs on cell

The calculators we use also runs on cell

The cells in these devices have some chemicals in them. These chemicals undergo redox reaction to produce electricity

These type of cells which produce electricity from chemical reactions are called galvanic cells

A galvanic cell can also be defined as a device which converts the chemical energy into electrical energy

Now we will see the construction of galvanic cell

For the construction of the galvanic cell, we use the above setup

The galvanic cell which is used as an example here is called a Daniel cell

The Daniel cell has two electrodes. One of these electrodes is cathode. It is the positively charged electrode

The second electrode is anode which is negatively charged

Reduction of copper will take place at the cathode in Daniel cell

Oxidation of zinc will take place at the anode in daniel cell

Electrolytes in the Daniel cell are and

A salt bridge is dipped in both the electrolytes

Salt bridge helps in completing the circuit

Salt bridge is made up of an ionic compound. It provides positive and negative ions to keep the solutions neutral

With maintaining neutrality, it also makes sure that the solutions do not mix with each other

Now we will see the working of this galvanic cell

When Daniel cell is turned on, zinc is oxidised at the anode

Zinc loses 2 electrons

Those 2 electrons travel through the wire to the cathode. These electrons add to Copper ions and copper gets reduced

So, this becomes the overall reaction in the cell

The movement of electrons from anode to cathode produces electricity

A voltmeter can be connected between the electrodes to measure the electric potential of the galvanic cell

As we can see in Daniel cell, oxidation and reduction reactions happen in different portions of the cell

At the anode, oxidation of zinc takes place. So this is called oxidation half reaction

Since oxidation half-reaction takes place at anode, this portion of the cell is called anode half cell

In anode half cell, both and exist at the same time

Since both oxidised form () and reduced form () are present in the container, they form a redox couple

Similarly at the cathode. reduction reaction will take place

At the cathode, reduction of copper takes place. So this is called reduction half reaction

Since reduction half-reaction takes place at cathode, this portion of the cell is called cathode half cell

In cathode half cell, both and exist at same time

Since both oxidised form () and reduced form () are present in the container, they also form a redox couple

Let’s revise

Galvanic cell convert chemical energy into electrical energy

The reduction will take place at cathode, known as reduction half-reaction. Oxidation will occur at the anode, known as oxidation half reaction

Salt bridge helps in completing the circuit. It makes sure that the solution remain neutral and do not mix with each other

The End