Which of the following is an example of a primary cell?

An example of a primary cell is an alkaline battery.

Primary cells are non-rechargeable batteries, meaning once they have been depleted of their energy, they cannot be recharged and must be replaced. These types of batteries are commonly found in everyday household items like remote controls, toys, and flashlights.

The alkaline battery works by converting chemical energy into electrical energy. Inside the battery, there are two electrodes - a negative electrode (anode) and a positive electrode (cathode). These electrodes are separated by an electrolyte, which allows the flow of ions between them.

During use, a chemical reaction occurs at the anode, causing zinc ions to be released into the electrolyte. At the cathode, manganese dioxide reacts with the zinc ions and water, producing hydroxide ions. The movement of ions creates an electron flow from the anode to the cathode, generating an electric current.

As the reactions continue, the zinc anode gradually gets consumed, and the battery loses its ability to produce electricity. Once the chemical reactions are complete, the alkaline battery is considered "dead" and needs to be replaced.

In contrast, the other options given are not primary cells:

• A fuel cell is an electrochemical cell that continuously converts fuel and an oxidizing agent into electricity. It differs from a primary cell because the reactants can be replenished, allowing it to produce electricity continuously.
• A lead-acid battery is a rechargeable battery, often used in automotive applications. It can be recharged by reversing the chemical reactions that occur during discharge.
• A lithium-ion battery is also a rechargeable battery commonly used in portable electronic devices. Similar to the lead-acid battery, its chemical reactions can be reversed through charging.