What are the electrodes used in a dry cell?

The electrodes used in a dry cell are zinc and graphite (carbon).

Dry cells are a common type of electrochemical cell used in many portable electronic devices. They use a paste electrolyte to minimize the risk of spillage, unlike wet cells that use liquid electrolytes. Understanding the electrodes used in a dry cell is crucial to understanding how it generates electricity.

Dry Cell Electrodes

A dry cell comprises two main electrodes:

• Anode (Negative Electrode): This is made of zinc (Zn). The zinc casing of the dry cell itself usually acts as the anode. Zinc undergoes oxidation, releasing electrons.

• Cathode (Positive Electrode): This is made of graphite (carbon). According to the provided reference, graphite is used as an electrode in the dry cell. The graphite rod is surrounded by a mixture of manganese dioxide (MnO₂), ammonium chloride (NH₄Cl), and carbon black. The graphite itself doesn't participate directly in the chemical reaction but serves as a conductor to carry electrons.

Here's a table summarizing the electrodes:

Electrode	Material	Polarity	Function
Anode	Zinc (Zn)	Negative	Oxidation occurs; releases electrons.
Cathode	Graphite (C)	Positive	Conducts electrons; surrounded by a reactive mixture.

Chemical Reactions in a Dry Cell

The following simplified reactions occur in a dry cell:

• At the Anode (Oxidation):

  Zn(s) → Zn²⁺(aq) + 2e^-

  Zinc atoms lose two electrons and become zinc ions.

• At the Cathode (Reduction):

  2MnO₂(s) + 2NH₄⁺(aq) + 2e^- → Mn₂O₃(s) + 2NH₃(aq) + H₂O(l)

  Manganese dioxide reacts with ammonium ions and electrons, forming manganese oxide, ammonia, and water.

The electrons released at the anode travel through the external circuit to the cathode, providing electrical energy. The ammonia produced can interfere with the reaction, so it is usually reacted with zinc ions to form complex ions, maintaining the cell's functionality.