Question

Describe the production of hydrogen gas by electrolysis. Can solar energy be used for this purpose? Why isn't water decomposed directly by absorption of sunlight?

Short answer

Hydrogen gas is produced by splitting water using electricity in electrolysis. Solar energy can provide the electricity needed. Regular sunlight doesn't decompose water because it lacks sufficient energy.

Step-by-step solution

What is Electrolysis?

Electrolysis is a chemical process where an electric current is passed through a substance to cause a chemical change. In the case of water, when electricity is applied, water is split into hydrogen and oxygen gases.

Electrolysis of Water

In the electrolysis of water, water (12O12) is decomposed into its component gases, hydrogen (12) and oxygen (02), by passing an electrical current through it. This chemical reaction takes place in an electrolytic cell.

Use of Solar Energy

Solar energy can be used in this process by providing the necessary electrical power through solar panels. This is an environmentally friendly method, as it uses renewable energy to produce hydrogen gas.

Sunlight Absorption and Water Decomposition

Water is not decomposed directly by sunlight because it does not absorb enough energy from regular sunlight to break the strong 12-O bonds. Therefore, additional energy (via electrical current) is needed to facilitate the decomposition through electrolysis.

Factors Against Direct Decomposition

The energy provided by sunlight is mostly in the form of heat and visible light, which are not sufficient to break water molecules apart directly. The electrical input is essential to provide the additional energy required to overcome the activation energy barrier of the decomposition process.

Key concepts

Electrolysis

Electrolysis is a fascinating process where electricity is employed to induce a chemical change in a substance. When we talk about electrolysis in the context of water, it refers to the use of an electric current to split water molecules into hydrogen and oxygen gases. This process occurs in an electrolytic cell, where water serves as the medium through which electricity passes. The importance of this process lies in its ability to produce hydrogen gas, a valuable source of clean energy.

During electrolysis, water molecules, represented chemically as H₂O, interact with the electric current. The molecules split apart, releasing hydrogen (H₂) at the cathode and oxygen (O₂) at the anode. This chemical reaction is beneficial due to the clean and efficient production of hydrogen without releasing harmful byproducts into the environment.

Solar Energy

Solar energy is a renewable energy source obtained from the sun and harnessed using solar panels. These panels convert sunlight into electricity, which can then be used for a variety of applications, including electrolysis. By supplying the electrical power necessary for electrolysis, solar energy offers a sustainable way to produce hydrogen gas.

Utilizing solar energy in electrolysis is advantageous because it helps reduce the reliance on fossil fuels. Solar panels capture photons from sunlight and convert them into electric power, which can be used immediately or stored for later use. By integrating solar energy into the hydrogen production process, we create a cycle that not only supports renewable energy but also minimizes carbon emissions.

Chemical Reaction

A chemical reaction is a process in which substances, known as reactants, are transformed into different substances, known as products. In the electrolysis of water, the key chemical reaction involves breaking the bonds of water molecules (H₂O) to produce hydrogen (H₂) and oxygen (O₂) gases.

This specific reaction is essential for understanding the production of hydrogen as it demonstrates the conversion of electrical energy into chemical energy. When an electric current is applied, it instigates the separation of hydrogen and oxygen atoms in water molecules. The energy input is crucial here, as it provides the necessary power to break the strong bonds between hydrogen and oxygen, eventually resulting in their release as gases.

Renewable Energy

Renewable energy refers to sources of energy that are sustainable and constantly replenished, such as solar, wind, and hydroelectric power. In the context of hydrogen production, renewable energy serves as a clean source of power for electrolysis.

Integrating renewable energy into the hydrogen production process is crucial for promoting a cleaner, more sustainable future. Unlike traditional fossil fuels, renewable energy sources do not deplete finite resources or contribute significantly to carbon emissions. By leveraging energy from the sun or wind to produce hydrogen through electrolysis, we can create a circular system that maintains environmental balance while meeting energy demands. This approach not only supports ecological goals but also drives innovation in energy solutions.