The formula of the basis of life - water is well-known. Its molecule consists of two hydrogen atoms and one oxygen, which is written as H2O. If there is twice as much oxygen, then a completely different substance will turn out - H2O2. What is it and how will the resulting substance differ from its “relative” water?
H2O2 - what is this substance?
Let's dwell on it in more detail. H2O2 is the formula for hydrogen peroxide, Yes, the same one that treats scratches, white. Hydrogen peroxide H2O2 - scientific name of the substance.
A 3% peroxide solution is used for disinfection. In pure or concentrated form, it causes chemical burns to the skin. A thirty percent peroxide solution is otherwise called perhydrol; it was previously used in hairdressing salons to bleach hair. The skin it burns also turns white.
Chemical properties of H2O2
Hydrogen peroxide is a colorless liquid with a "metallic" taste. It is a good solvent and easily dissolves itself in water, ether, alcohols.
Three and six percent peroxide solutions are usually prepared by diluting a thirty percent solution. When concentrated H2O2 is stored, the substance decomposes with the release of oxygen, therefore, in tightly sealedIt should not be stored in containers in order to avoid an explosion. With a decrease in the concentration of peroxide, its stability increases. Also, to slow down the decomposition of H2O2, various substances can be added to it, for example, phosphoric or salicylic acid. To store solutions of strong concentration (more than 90 percent), sodium pyrophosphate is added to the peroxide, which stabilizes the state of the substance, and aluminum vessels are also used.
H2O2 in chemical reactions can be both an oxidizing agent and a reducing agent. More often, however, peroxide exhibits oxidizing properties. Peroxide is considered to be an acid, but a very weak one; hydrogen peroxide s alts are called peroxides.
The decomposition reaction as a method for producing oxygen
The decomposition reaction of H2O2 occurs when a substance is exposed to high temperature (more than 150 degrees Celsius). The result is water and oxygen.
Reaction formula - 2 H2O2 + t -> 2 H2O + O2
You can calculate the electronic balance of H2O2 in the equation:
Oxidation state of H to H2O2 and H2O=+1.
Oxidation state O: in H2O2=-1, in H2 O=-2, in O2=02 O
-1 - 2e -> O2 0
O-1 + e -> O-2
2 H2O2=2 H2O + O2
Decomposition of hydrogen peroxide can also occur at room temperature if a catalyst (a chemical that speeds up the reaction) is used.
In laboratories, one of the methods for obtaining oxygen, along with decompositionberthollet s alt or potassium permanganate, is the decomposition reaction of peroxide. In this case, manganese (IV) oxide is used as a catalyst. Other substances that accelerate the decomposition of H2O2 are copper, platinum, sodium hydroxide.
History of the discovery of peroxide
The first steps towards the discovery of peroxide were made in 1790 by the German Alexander Humboldt, when he discovered the transformation of barium oxide into peroxide when heated. That process was accompanied by the absorption of oxygen from the air. Twelve years later, scientists Tenard and Gay-Lussac conducted an experiment on the combustion of alkali metals with excess oxygen, resulting in sodium peroxide. But hydrogen peroxide was obtained later, only in 1818, when Louis Tenard studied the effect of acids on metals; for their stable interaction, a low amount of oxygen was needed. Conducting a confirmatory experiment with barium peroxide and sulfuric acid, the scientist added water, hydrogen chloride and ice to them. After a short time, Tenar found small solidified drops on the walls of the container with barium peroxide. It became clear that it was H2O2. Then they gave the resulting H2O2 the name "oxidized water". This was hydrogen peroxide - a colorless, odorless, hardly evaporable liquid that dissolves other substances well. The result of the interaction of H2O2 and H2O2 is a dissociation reaction, the peroxide is soluble in water.
An interesting fact - the properties of the new substance were quickly discovered, allowing it to be used in restoration work. Tenard himself restored the painting with peroxide. Raphael, darkened by age.
Hydrogen peroxide in the 20th century
After a thorough study of the resulting substance, it began to be produced on an industrial scale. At the beginning of the twentieth century, an electrochemical technology for the production of peroxide was introduced, based on the electrolysis process. But the shelf life of the substance obtained by this method was small, about a couple of weeks. Pure peroxide is unstable, and most of it was produced at 30% for bleaching fabrics, and 3% or 6% for household use.
Scientists of Nazi Germany used peroxide to create a liquid fuel rocket engine, which was used for defense needs in the Second World War. As a result of the interaction of H2O2 and methanol / hydrazine, a powerful fuel was obtained, on which the aircraft reached speeds of more than 950 km / h.
Where is H2O2 used now?
- in medicine - for the treatment of wounds;
- the bleaching properties of the substance are used in the pulp and paper industry;
- in the textile industry, natural and synthetic fabrics, furs, wool are bleached with peroxide;
- as rocket fuel or its oxidizer;
- in chemistry - to produce oxygen, as a foaming agent for the production of porous materials, as a catalyst or hydrogenating agent;
- for the production of disinfectants or cleaning products, bleaches;
- for bleaching hair (this is an outdated method, as hair is badly damaged by peroxide);
- Some people use peroxide to whiten their teeth, but it destroys their enamel;
- Aquarists and fish farms use a 3% H2O2 solution to revive suffocated fish, to kill algae and parasites in the aquarium, and to combat certain fish diseases;
- in all industries, peroxide can be used as a disinfectant for surfaces, equipment, packaging;
- for pool cleaning;
- for the extraction of metals and oil in the mining and oil industry;
- for processing metals and alloys in metalworking.
Use of H2O2 in everyday life
Hydrogen peroxide can be successfully used to solve various household problems. But only 3% hydrogen peroxide can be used for these purposes. Here are some ways:
- To clean surfaces, pour peroxide into a vessel with a spray bottle and spray on contaminated areas.
- To disinfect objects, wipe them with undiluted H2O2 solution. This will help cleanse them of harmful microorganisms. Washing sponges can be soaked in water with peroxide (proportion 1:1).
- To bleach fabrics when washing white things, add a glass of peroxide. You can also rinse white fabrics in water mixed with a glass of H2O2. This method restores whiteness, prevents fabrics from yellowing, and helps remove stubborn stains.
- To combat mold and fungus, mix peroxide and water in a 1:2 ratio in a spray bottle. Spray the resulting mixture onto contaminated surfaces andafter 10 minutes, clean them with a brush or sponge.
- You can renew the darkened grout in tiles by spraying peroxide on the desired areas. After 30 minutes, rub them thoroughly with a stiff brush.
- To wash dishes, add half a glass of H2O2 to a full basin of water (or a sink with a closed drain). Cups and plates washed in this solution will shine with cleanliness.
- To clean your toothbrush, dip it in an undiluted 3% peroxide solution. Then rinse under strong running water. This method disinfects the hygiene item well.
- To disinfect purchased vegetables and fruits, spray them with a solution of 1 part peroxide and 1 part water, then rinse them thoroughly with water (can be cold).
- In the summer cottage, with the help of H2O2, you can fight plant diseases. You need to spray them with a peroxide solution or soak the seeds shortly before planting in 4.5 liters of water mixed with 30 ml of forty percent hydrogen peroxide.
- To revive aquarium fish, if they are poisoned by ammonia, suffocated when aeration is turned off, or for another reason, you can try placing them in water with hydrogen peroxide. It is necessary to mix 3% peroxide with water at the rate of 30 ml per 100 liters and place it in the resulting mixture of lifeless fish for 15-20 minutes. If they do not come to life during this time, then the remedy did not help.
Hydrogen peroxide in nature
Hydrogen peroxide should not be considered an artificial compound obtained only in laboratories. In H2O2found in rain and snow, in mountain air. In the mountains you can find springs and rivers with white water from the smallest oxygen bubbles, which is rightly considered useful. Few people know that the color and bubbles are due to the presence of H2O2 in the water, which is formed due to its good aeration. Meanwhile, one should not be afraid to drink such unboiled water, unless, of course, there are plants and factories nearby. Hydrogen peroxide, found naturally in water, acts as a disinfectant against microorganisms and parasites.
Even vigorously shaking a water bottle produces some peroxide, as the water is saturated with oxygen.
Fresh fruits and vegetables also contain H2O2 until they are cooked. During heating, boiling, roasting and other processes with an accompanying high temperature, a large amount of oxygen is destroyed. That is why cooked foods are considered not so useful, although some amount of vitamins remains in them. Freshly squeezed juices or oxygen cocktails served in sanatoriums are useful for the same reason - due to oxygen saturation, which gives the body new strength and cleanses it.
Danger of peroxide ingestion
After the above, it may seem that peroxide can be specifically taken orally, and this will benefit the body. But that's not the case at all. In water or juices, the compound is found in minimal amounts and is closely related to other substances. Taking "unnatural" hydrogen peroxide inside(and all peroxide, bought in a store or produced as a result of chemical experiments on its own, cannot be considered natural in any way, moreover, it has too high a concentration compared to natural) can lead to life-threatening and he alth consequences. To understand why, we need to revisit chemistry.
As already mentioned, under certain conditions, hydrogen peroxide breaks down and releases oxygen, which is an active oxidizing agent. For example, a decomposition reaction can occur when H2O2 collides with peroxidase, an intracellular enzyme. The use of peroxide for disinfection is based on its oxidizing properties. So, when a wound is treated with H2O2, the released oxygen destroys the living pathogenic microorganisms that have entered it. It has the same effect on other living cells. If you treat undamaged skin with peroxide and then wipe the treated area with alcohol, you will feel a burning sensation, which confirms the presence of microscopic damage after peroxide. But with the external use of peroxide at a low concentration, there will be no noticeable harm to the body.
Another thing if you try to take it inside. The substance that can damage even relatively thick skin from the outside gets on the mucous membranes of the digestive tract. That is, chemical mini-burns occur. Of course, the released oxidizing agent - oxygen - can also kill harmful microbes. But the same process will occur with the cells of the alimentary tract. If burns as a result of actionoxidizing agent will be repeated, then atrophy of the mucous membranes is possible, and this is the first step towards cancer. The death of intestinal cells leads to the inability of the body to absorb nutrients, this explains, for example, weight loss and the disappearance of constipation in some people who practice peroxide "treatment".
Separately, it must be said about such a method of using peroxide as intravenous injections. Even if for some reason they were prescribed by a doctor (this can only be justified in case of blood poisoning, when there are no other suitable drugs available), then under medical supervision and with a strict calculation of dosages, there are still risks. But in such an extreme situation, it will be a chance for recovery. In no case should you prescribe yourself injections of hydrogen peroxide. H2O2 poses a great danger to blood cells - erythrocytes and platelets, as it destroys them when it enters the bloodstream. In addition, a deadly blockage of blood vessels by the released oxygen can occur - a gas embolism.
Safety measures for handling H2O2
- Keep out of the reach of children and infirm persons. The lack of smell and pronounced taste makes peroxide especially dangerous for them, as large doses can be taken. If the solution is ingested, the consequences of use can be unpredictable. Seek medical attention immediately.
- Peroxide solutions with a concentration of more than three percent cause burns on contact with the skin. The burnt area should be washed with plenty of water.
- Do not allow the peroxide solution to get into the eyes, as their swelling, redness, irritation, and sometimes pain are formed. First aid before going to the doctor - flushing the eyes with plenty of water.
- Keep the substance in a way that it is clear that it is H2O2, that is, in a container with a sticker to avoid accidental misuse.
- Storage conditions that extend its life - dark, dry, cool place.
- Do not mix hydrogen peroxide with any liquids other than clean water, including chlorinated tap water.
- All of the above applies not only to H2O2, but to all preparations containing it.
