Hydrogen peroxide is a bubbly, antimicrobial agent.
In this lesson, we will learn how it is used, what its physical and chemical properties are, and how it is prepared.
What Is Hydrogen Peroxide?
You may remember when you’d get a cut as a child that your mom may have poured something over the wound. It would sting but at the same time it was very intriguing because it would bubble and fizz.
This fascinating liquid is called hydrogen peroxide. The bubbles happen when the hydrogen peroxide reacts with your living cells causing them to break down into water and oxygen. The oxygen would escape in bubbles, making the hydrogen peroxide bubble and fizz.Today, doctors suggest not using hydrogen peroxide as an antiseptic on wounds because it causes the wound to heal slower. But it’s still a disinfectant for many different surfaces and objects, including surgical instruments. Since it does break down into two very harmless compounds, water and oxygen, it’s seen as an environmentally friendly antimicrobial.
If you were to do an Internet search for uses of hydrogen peroxide, you would come up with a large list. Hydrogen peroxide can be found in glow sticks and rocket fuel, and can be used as an explosive or as a bleach for hair, paper, or flour. It’s also used as a common alternative medicine treatment.
Hydrogen Peroxide Properties
Many of the physical properties of hydrogen peroxide are similar to water. The melting point for hydrogen peroxide is -0.4 degrees Celsius, and the boiling point is 150 degrees Celsius. So the melting point is very similar to that of water (which is 0 degrees Celsius), but the boiling point is much higher than the boiling point of water (which is 100 degrees Celsius). Although we do need to note that the boiling point for hydrogen peroxide is only theoretical. We’ve never actually been able to boil hydrogen peroxide because, as we heat up hydrogen peroxide, it explodes and decomposes into water and oxygen.Hydrogen peroxide has each oxygen connected to the other oxygen and to one of the hydrogen atoms.
This structure is not in a planar molecule but instead has a twisted symmetry. The bond angle between each oxygen and hydrogen is 102 degrees.Hydrogen peroxide is a strong oxidizing agent. It’s only in the presence of very strong oxidizing agent, such as magnesium oxide, that it can act as a reducing agent. When hydrogen peroxide acts as an oxidizing agent, it gives up one of the oxygen atoms, leaving behind water as a byproduct.
Hydrogen Peroxide Preparation
There are many different ways that hydrogen peroxide can be prepared. Generally, it’s prepared through oxidation of a hydroquinone.
Oxidation is when more carbon-oxygen bonds are formed. A hydroquinone is an aromatic compound derived from benzene, which acts as the source of hydrogens in the hydrogen peroxide.The general equation for making hydrogen peroxide is to simply combine hydrogen with oxygen and hydrogen peroxide is formed.
The hydroquinone method, also called the electrolysis method, uses hydroquinone as the hydrogen source to make hydrogen peroxide. The nice thing about this method is that if hydrogens on a metal catalyst are in the presence of the resulting product, the anthraquinone, they can be recycled and used as another hydroquinone to create more hydrogen peroxide.
In this image, you can see that first we have hydroquinone. In the presence of oxygen this hydroquinone will oxidize into anthraquinone.
Since the carbon-oxygen bond is now a double bond, there are now more carbon oxygen bonds making it oxidized. The hydrogens, which were on the oxygen, now combine with the oxygen to form hydrogen peroxide. Then, we see that the resulting anthraquinone can be exposed to hydrogen to reform the hydroquinone, and the reaction cycles back to the beginning. It isn’t shown on the image but this hydrogen is on a metal catalyst.
Hydrogen peroxide is used as an environmentally-friendly antimicrobial and bleaching agent, since its byproducts are simply oxygen and water. Its structure is similar to water, and its melting point is also very similar to water (both are about 0 degrees Celsius). However, the boiling point is much higher than water, at 150 degrees Celsius.
While it’s a great disinfecting agent for many things, doctors tend to not recommend using it on wounds anymore, because it slows the healing process.It’s a nonplanar molecular with twisted symmetry and acts as a strong oxidizing agent. It’s prepared by using a hydrogen source and combining it with oxygen. The most common method uses oxidation, which is when more carbon-oxygen bonds are formed, to oxidize hydroquinone, an aromatic compound derived from benzene, which acts as the source of hydrogens in the hydrogen peroxide, which acts as the hydrogen source. The product can then be recycled back to be used as a new hydrogen source.