Question

Which substance is used as a depolarizer in a Leclanche cell?

Answer 1

Hint:
Leclanche cell, commonly known as the dry cell, produces electricity from chemical reactions. Depolarizer is an electrochemical substance, which either changes its oxidation state to facilitate the chemical reaction or facilitates the breaking and forming of chemical bonds.

Complete step-by-step answer:
Leclanche cell is an electrochemical battery invented by Georges Leclanche. It contains the following:
An electrolytic solution, which is ammonium chloride here.
A cathode or the positive terminal, namely the carbon rod.
An anode or the negative terminal, namely the zinc rod.
And a depolarizer, namely the manganese dioxide.
Thus the depolarizer used in the Leclanche cell is manganese dioxide.
Additional Information:
The redox reaction, between the cathode and anode rods, produces free electrons, which in turn produce electricity. The electrons in the circuit combine with the depolarizer, which is manganese dioxide and water to release negatively charged hydrogen ions, which facilitates the reaction. The discovery of Leclanche cells, later led to the manufacturing of dry cells and the branch of chemistry called electrochemistry.
This setup produces about \[1.4V\]emf, which is sufficient for electric bells and signalling. Also these batteries require little to no maintenance.

Note: Leclanche cell is an electrochemical battery, which consists of various elements. An electrolytic solution is different from depolarizer, as electrolytic solution helps in the movement of the electrons produced in the cell, and doesn’t take part in the reaction. Whereas, the depolarizer takes active part in the reaction, either by varying its oxidation state, or facilitating the breaking and forming of chemical bonds .