Why are some batteries labelled "alkaline"?

Some batteries are labelled "alkaline" because they use an alkaline electrolyte, typically potassium hydroxide, in their chemical reaction.

Alkaline batteries are a type of primary battery, meaning they are non-rechargeable. They are named after the alkaline electrolyte used in them, which is usually potassium hydroxide. This is a basic substance, hence the term 'alkaline'. The alkaline electrolyte is a key component in the battery's operation, as it facilitates the movement of ions between the battery's electrodes during discharge, enabling the flow of electric current.

The chemical reaction in an alkaline battery involves the anode, the negative electrode, and the cathode, the positive electrode. The anode is typically made of zinc powder, which increases the surface area for the reaction, and the cathode is usually composed of manganese dioxide. When the battery is connected to a device and begins to discharge, the zinc at the anode is oxidised, releasing electrons. These electrons then flow through the external circuit to the cathode, where the manganese dioxide is reduced, accepting the electrons.

The alkaline electrolyte, potassium hydroxide, plays a crucial role in this process. It allows the transfer of ions between the anode and cathode, completing the circuit and enabling the flow of electric current. Without the electrolyte, the chemical reactions at the electrodes could not occur, and the battery would not produce electricity.

Alkaline batteries are popular due to their long shelf life and high energy density. They can deliver a good amount of energy for their size and weight, making them suitable for many portable devices. Furthermore, they operate well in a wide range of temperatures, and their performance is generally superior to that of other types of non-rechargeable batteries, such as zinc-carbon batteries. However, they are more expensive to produce due to the cost of the materials used.

In summary, the term 'alkaline' in alkaline batteries refers to the alkaline electrolyte used in the battery's chemical reaction. This electrolyte is essential for the battery's operation, facilitating the movement of ions and enabling the flow of electric current.