Conversion of Chemical Energy into Electrical Energy in a Battery

The correct answer to the question is option 'C' - a battery. A battery is a device that converts chemical energy into electrical energy through a chemical reaction. It consists of one or more electrochemical cells, which are composed of two electrodes (a cathode and an anode) and an electrolyte.

Chemical Reactions in a Battery:

When a battery is connected to an external circuit, a chemical reaction occurs within the battery. This chemical reaction involves the transfer of electrons from the anode to the cathode through the external circuit. The chemical reaction is typically a redox reaction (oxidation-reduction reaction), where one electrode undergoes oxidation (loses electrons) and the other undergoes reduction (gains electrons).

Here is a breakdown of the chemical reactions that occur in a typical battery:

1. Anode Reaction: At the anode, oxidation takes place, and the anode material loses electrons. For example, in a typical alkaline battery, the anode reaction is:

Zn(s) -> Zn2+(aq) + 2e-

In this reaction, zinc metal (Zn) is oxidized to form zinc ions (Zn2+) and release two electrons (2e-).

2. Cathode Reaction: At the cathode, reduction takes place, and the cathode material gains electrons. For example, in a typical alkaline battery, the cathode reaction is:

2MnO2(s) + H2O(l) + 2e- -> Mn2O3(s) + 2OH-(aq)

In this reaction, manganese dioxide (MnO2) is reduced by gaining two electrons (2e-) and reacts with water (H2O) to form manganese(III) oxide (Mn2O3) and hydroxide ions (OH-).

3. Overall Reaction: The overall reaction in a battery is the sum of the anode and cathode reactions. In the case of an alkaline battery, the overall reaction is:

Zn(s) + 2MnO2(s) + H2O(l) -> Zn2+(aq) + Mn2O3(s) + 2OH-(aq)

This overall reaction releases energy in the form of electrical potential energy, which can be harnessed to do work in an external circuit.

Conversion of Chemical Energy to Electrical Energy:

The conversion of chemical energy into electrical energy occurs due to the movement of electrons from the anode to the cathode through the external circuit. This flow of electrons creates an electric current, which can be used to power various devices or perform work.

The chemical reactions in the battery result in a potential difference, or voltage, between the anode and cathode. This potential difference drives the movement of electrons, creating an electric current. The electrical energy produced can then be used to power devices such as flashlights, remote controls, smartphones, and many more.

In summary, a battery converts chemical energy into electrical energy through a redox reaction. The anode undergoes oxidation, losing electrons, while the cathode undergoes reduction, gaining electrons. The movement of electrons through the external circuit creates an electric current, which can be used to power various devices.