Chemical properties of hydrogen: features and applications. Physical and chemical properties of hydrogen
Hydrogen is a special element that occupies two cells at once in Mendeleev’s periodic table. It is located in two groups of elements that have opposite properties, and this feature makes it unique. Hydrogen is a simple substance and an integral part of many complex compounds; it is an organogenic and biogenic element. It is worth familiarizing yourself in detail with its main features and properties.
Hydrogen in the periodic table of Mendeleev
The main features of hydrogen indicated in:
- the serial number of the element is 1 (there are the same number of protons and electrons);
- atomic mass is 1.00795;
- hydrogen has three isotopes, each of which has special properties;
- due to the content of only one electron, hydrogen is capable of exhibiting reducing and oxidizing properties, and after donating an electron, hydrogen has a free orbital that takes part in the formation of chemical bonds according to the donor-acceptor mechanism;
- hydrogen is a light element with low density;
- hydrogen is a strong reducing agent, it opens the group of alkali metals in the first group to the main subgroup;
- when hydrogen reacts with metals and other strong reducing agents, it accepts their electron and becomes an oxidizing agent. Such compounds are called hydrides. According to this characteristic, hydrogen conventionally belongs to the group of halogens (in the table it is given above fluorine in brackets), with which it is similar.
Hydrogen as a simple substance
Hydrogen is a gas whose molecule consists of two. This substance was discovered in 1766 by the British scientist Henry Cavendish. He proved that hydrogen is a gas that explodes when it reacts with oxygen. After studying hydrogen, chemists found that this substance is the lightest of all known to man.
Another scientist, Lavoisier, gave the element the name “hydrogenium,” which translated from Latin means “giving birth to water.” In 1781, Henry Cavendish proved that water is a combination of oxygen and hydrogen. In other words, water is the product of the reaction of hydrogen with oxygen. The flammable properties of hydrogen were known to ancient scientists: the corresponding records were left by Paracelsus, who lived in the 16th century.
Molecular hydrogen is a naturally occurring gaseous compound common in nature, which consists of two atoms and when brought to the surface of a burning splinter. A hydrogen molecule can disintegrate into atoms that turn into helium nuclei, as they are capable of participating in nuclear reactions. Such processes regularly occur in space and on the Sun.
Hydrogen and its physical properties
Hydrogen has the following physical parameters:
- boils at -252.76 °C;
- melts at -259.14 °C; *within the specified temperature limits, hydrogen is an odorless, colorless liquid;
- Hydrogen is slightly soluble in water;
- hydrogen can theoretically transform into a metallic state if special conditions are provided (low temperatures and high pressure);
- pure hydrogen is an explosive and flammable substance;
- hydrogen is able to diffuse through the thickness of metals, therefore it dissolves well in them;
- hydrogen is 14.5 times lighter than air;
- At high pressure, snow-like crystals of solid hydrogen can be obtained.
Chemical properties of hydrogen
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Laboratory methods:
- interaction of dilute acids with active metals and metals of intermediate activity;
- hydrolysis of metal hydrides;
- reaction of alkali and alkaline earth metals with water.
Hydrogen compounds:
Hydrogen halides; volatile hydrogen compounds of non-metals;
hydrides;
To test the purity of hydrogen, you need to hold a lit match to the neck of the test tube. If a dull and quiet bang occurs, the gas is clean and air impurities are minimal. If the cotton is loud and whistling, the gas in the test tube is dirty and contains a large proportion of foreign components.
Attention! Do not try to repeat these experiments yourself!
Let's look at what hydrogen is. The chemical properties and production of this non-metal are studied in the inorganic chemistry course at school. It is this element that heads Mendeleev’s periodic table, and therefore deserves a detailed description.
Brief information about opening an element
Before looking at the physical and chemical properties of hydrogen, let's find out how this important element was found.
Chemists who worked in the sixteenth and seventeenth centuries repeatedly mentioned in their writings the flammable gas that is released when acids are exposed to active metals. In the second half of the eighteenth century, G. Cavendish managed to collect and analyze this gas, giving it the name “combustible gas.”
The physical and chemical properties of hydrogen were not studied at that time. Only at the end of the eighteenth century A. Lavoisier was able to establish through analysis that this gas could be obtained by analyzing water. A little later, he began to call the new element hydrogene, which translated means “giving birth to water.” Hydrogen owes its modern Russian name to M. F. Solovyov.
Being in nature
The chemical properties of hydrogen can only be analyzed based on its occurrence in nature. This element is present in the hydro- and lithosphere, and is also part of minerals: natural and associated gas, peat, oil, coal, oil shale. It is difficult to imagine an adult who would not know that hydrogen is a component of water.
In addition, this non-metal is found in animal bodies in the form of nucleic acids, proteins, carbohydrates, and fats. On our planet, this element is found in free form quite rarely, perhaps only in natural and volcanic gas.
In the form of plasma, hydrogen makes up approximately half the mass of stars and the Sun, in addition, it is part of the interstellar gas. For example, in free form, as well as in the form of methane and ammonia, this non-metal is present in comets and even some planets.
Physical properties
Before considering the chemical properties of hydrogen, we note that under normal conditions it is a gaseous substance lighter than air, having several isotopic forms. It is almost insoluble in water and has high thermal conductivity. Protium, which has a mass number of 1, is considered its lightest form. Tritium, which has radioactive properties, is formed in nature from atmospheric nitrogen when neurons expose it to UV rays.
Features of the structure of the molecule
To consider the chemical properties of hydrogen and the reactions characteristic of it, let us dwell on the features of its structure. This diatomic molecule contains a covalent nonpolar chemical bond. The formation of atomic hydrogen is possible through the interaction of active metals with acid solutions. But in this form, this non-metal can exist only for a short period of time; almost immediately it recombines into a molecular form.
Chemical properties
Let's consider the chemical properties of hydrogen. In most of the compounds that this chemical element forms, it exhibits an oxidation state of +1, which makes it similar to active (alkali) metals. The main chemical properties of hydrogen that characterize it as a metal:
- interaction with oxygen to form water;
- reaction with halogens, accompanied by the formation of hydrogen halide;
- producing hydrogen sulfide by combining with sulfur.
Below is the equation for reactions characterizing the chemical properties of hydrogen. Please note that as a non-metal (with oxidation state -1) it acts only in reaction with active metals, forming corresponding hydrides with them.
Hydrogen at ordinary temperatures reacts inactively with other substances, so most reactions occur only after preheating.
Let us dwell in more detail on some of the chemical interactions of the element that heads Mendeleev’s periodic system of chemical elements.
The reaction of water formation is accompanied by the release of 285.937 kJ of energy. At elevated temperatures (more than 550 degrees Celsius), this process is accompanied by a strong explosion.
Among those chemical properties of hydrogen gas that have found significant application in industry, its interaction with metal oxides is of interest. It is through catalytic hydrogenation that in modern industry metal oxides are processed, for example, pure metal is isolated from iron scale (mixed iron oxide). This method allows for efficient recycling of scrap metal.
Ammonia synthesis, which involves the interaction of hydrogen with air nitrogen, is also in demand in the modern chemical industry. Among the conditions for this chemical interaction, we note pressure and temperature.
Conclusion
It is hydrogen that is a low-active chemical substance under normal conditions. As the temperature rises, its activity increases significantly. This substance is in demand in organic synthesis. For example, hydrogenation can reduce ketones to secondary alcohols and convert aldehydes to primary alcohols. In addition, by hydrogenation it is possible to convert unsaturated hydrocarbons of the ethylene and acetylene class into saturated compounds of the methane series. Hydrogen is rightfully considered a simple substance in demand in modern chemical production.
Characteristics of s-elements
The block of s-elements includes 13 elements, common to which is the building of an external energy level in their s-sublevel atoms.
Although hydrogen and helium are classified as s-elements, due to the specific nature of their properties, they should be considered separately. Hydrogen, sodium, potassium, magnesium, calcium are vital elements.
Compounds of s-elements exhibit general patterns in their properties, which is explained by the similarity of the electronic structure of their atoms. All outer electrons are valence electrons and take part in the formation of chemical bonds. Therefore, the maximum oxidation state of these elements in compounds is equal to number electrons in the outer layer and is accordingly equal to the number of the group in which the element is located. The oxidation state of s-element metals is always positive. Another feature is that after the electrons of the outer layer are separated, an ion with a noble gas shell remains. As the atomic number of an element or atomic radius increases, the ionization energy decreases (from 5.39 eV y Li to 3.83 eV y Fr), and the reduction activity of the elements increases.
The vast majority of compounds of s-elements are colorless (unlike compounds of d-elements), since the transition of d-electrons from low energy levels to higher energy levels, which causes color, is excluded.
Compounds of elements of groups IA - IIA are typical salts; in an aqueous solution they almost completely dissociate into ions and are not subject to cation hydrolysis (except for Be 2+ and Mg 2+ salts).
hydrogen hydride ionic covalent
Complexation is not typical for s-element ions. Crystalline complexes of s - elements with ligands H 2 O-crystalline hydrates have been known since ancient times, for example: Na 2 B 4 O 7 10H 2 O-borax, KAl (SO 4) 2 12H 2 O-alum. Water molecules in crystalline hydrates are grouped around the cation, but sometimes completely surround the anion. Due to the small ion charge and large ion radius, alkali metals are least prone to forming complexes, including aqua complexes. Lithium, beryllium, and magnesium ions act as complexing agents in complex compounds of low stability.
Hydrogen. Chemical properties of hydrogen
Hydrogen is the lightest s-element. Its electronic configuration in the ground state is 1S 1. A hydrogen atom consists of one proton and one electron. The peculiarity of hydrogen is that its valence electron is located directly in the sphere of action of the atomic nucleus. Hydrogen does not have an intermediate electron layer, so hydrogen cannot be considered an electronic analogue of alkali metals.
Like alkali metals, hydrogen is a reducing agent and exhibits an oxidation state of +1. The spectra of hydrogen are similar to the spectra of alkali metals. What makes hydrogen similar to alkali metals is its ability to produce a hydrated, positively charged H + ion in solutions.
Like a halogen, the hydrogen atom is missing one electron. This determines the existence of the H - hydride ion.
In addition, like halogen atoms, hydrogen atoms are characterized by a high ionization energy (1312 kJ/mol). Thus, hydrogen occupies a special position in the Periodic Table of Elements.
Hydrogen is the most abundant element in the universe, accounting for up to half the mass of the sun and most stars.
On the sun and other planets, hydrogen is in the atomic state, in the interstellar medium in the form of partially ionized diatomic molecules.
Hydrogen has three isotopes; protium 1 H, deuterium 2 D and tritium 3 T, and tritium is a radioactive isotope.
Hydrogen molecules are distinguished by high strength and low polarizability, small size and low mass, and have high mobility. Therefore, hydrogen has very low melting points (-259.2 o C) and boiling points (-252.8 o C). Due to the high dissociation energy (436 kJ/mol), the disintegration of molecules into atoms occurs at temperatures above 2000 o C. Hydrogen is a colorless gas, odorless and tasteless. It has a low density - 8.99·10 -5 g/cm At very high pressures, hydrogen transforms into a metallic state. It is believed that on the distant planets of the solar system - Jupiter and Saturn, hydrogen is in a metallic state. There is an assumption that the composition of the earth's core also includes metallic hydrogen, where it is found at ultra-high pressure created by the earth's mantle.
Chemical properties. At room temperature, molecular hydrogen reacts only with fluorine, when irradiated with light - with chlorine and bromine, and when heated with O 2, S, Se, N 2, C, I 2.
Reactions of hydrogen with oxygen and halogens proceed by a radical mechanism.
Interaction with chlorine is an example of an unbranched reaction when irradiated with light (photochemical activation) or when heated (thermal activation).
Сl+ H2 = HCl + H (chain development)
H+ Cl 2 = HCl + Cl
The explosion of a detonating gas - a hydrogen-oxygen mixture - is an example of a branched chain process, when the initiation of the chain includes not one, but several stages:
H 2 + O 2 = 2OH
H+ O 2 = OH+O
O+ H 2 = OH+ H
OH + H 2 = H 2 O + H
An explosion process can be avoided if you work with pure hydrogen.
Since hydrogen is characterized by a positive (+1) and negative (-1) oxidation state, hydrogen can exhibit both reducing and oxidizing properties.
The reducing properties of hydrogen manifest themselves when interacting with non-metals:
H 2 (g) + Cl 2 (g) = 2HCl (g),
2H 2 (g) + O 2 (g) = 2H 2 O (g),
These reactions proceed with the release of a large amount of heat, which indicates the high energy (strength) of the H-Cl, H-O bonds. Therefore, hydrogen exhibits reducing properties towards many oxides and halides, for example:
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This is the basis for the use of hydrogen as a reducing agent for the production of simple substances from halide oxides.
An even stronger reducing agent is atomic hydrogen. It is formed from a molecular electron discharge under low pressure conditions.
Hydrogen has a high reducing activity at the moment of release during the interaction of a metal with an acid. This hydrogen reduces CrCl 3 to CrCl 2:
2CrCl 3 + 2HCl + 2Zn = 2CrCl 2 + 2ZnCl 2 +H 2 ^
The interaction of hydrogen with nitrogen oxide (II) is important:
2NO + 2H2 = N2 + H2O
Used in purification systems for the production of nitric acid.
As an oxidizing agent, hydrogen interacts with active metals:
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In this case, hydrogen behaves like a halogen, forming similar to halides hydrides.
Hydrides of s-elements of group I have an ionic structure of the NaCl type. Chemically, ionic hydrides behave like basic compounds.
Covalent hydrides include hydrides of non-metallic elements that are less electronegative than hydrogen itself, for example, hydrides of the composition SiH 4, BH 3, CH 4. By chemical nature, non-metal hydrides are acidic compounds.
A characteristic feature of the hydrolysis of hydrides is the release of hydrogen; the reaction proceeds via a redox mechanism.
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Basic hydride
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Acid hydride
Due to the release of hydrogen, hydrolysis proceeds completely and irreversibly (?H<0, ?S>0). In this case, basic hydrides form alkali, and acidic hydrides form acid.
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The standard potential of the system is B. Therefore, the H ion is a strong reducing agent.
In the laboratory, hydrogen is produced by reacting zinc with 20% sulfuric acid in a Kipp apparatus.
Technical zinc often contains small impurities of arsenic and antimony, which are reduced by hydrogen at the time of release to poisonous gases: arsine SbH 3 and stabine SbH This hydrogen can poison you. With chemically pure zinc, the reaction proceeds slowly due to overvoltage and a good current of hydrogen cannot be obtained. The rate of this reaction is increased by adding crystals of copper sulfate; the reaction is accelerated by the formation of a Cu-Zn galvanic couple.
More pure hydrogen is formed by the action of alkali on silicon or aluminum when heated:
In industry, pure hydrogen is produced by electrolysis of water containing electrolytes (Na 2 SO 4, Ba (OH) 2).
A large amount of hydrogen is produced as a by-product during the electrolysis of an aqueous sodium chloride solution with a diaphragm separating the cathode and anode spaces,
The largest amount of hydrogen is obtained by gasification of solid fuel (anthracite) with superheated water steam:
Or by conversion of natural gas (methane) with superheated steam:
The resulting mixture (synthesis gas) is used in the production of many organic compounds. The yield of hydrogen can be increased by passing synthesis gas over the catalyst, which converts CO into CO 2 .
Application. A large amount of hydrogen is consumed in the synthesis of ammonia. For the production of hydrogen chloride and hydrochloric acid, for the hydrogenation of vegetable fats, for the recovery of metals (Mo, W, Fe) from oxides. Hydrogen-oxygen flame is used for welding, cutting and melting metals.
Liquid hydrogen is used as rocket fuel. Hydrogen fuel is environmentally friendly and more energy-intensive than gasoline, so in the future it can replace petroleum products. Already, several hundred cars in the world are powered by hydrogen. The problems of hydrogen energy are related to the storage and transportation of hydrogen. Hydrogen is stored in underground tankers in a liquid state under a pressure of 100 atm. Transporting large quantities of liquid hydrogen poses serious risks.
Oxygen is the most abundant element on Earth. Together with nitrogen and a small amount of other gases, free oxygen forms the Earth's atmosphere. Its content in the air is 20.95% by volume or 23.15% by mass. In the earth's crust, 58% of the atoms are bound oxygen atoms (47% by mass). Oxygen is part of water (the reserves of bound oxygen in the hydrosphere are extremely large), rocks, many minerals and salts, and is found in fats, proteins and carbohydrates that make up living organisms. Almost all of the Earth's free oxygen is created and preserved as a result of the process of photosynthesis.
Physical properties.
Oxygen is a colorless, tasteless, and odorless gas, slightly heavier than air. It is slightly soluble in water (31 ml of oxygen dissolves in 1 liter of water at 20 degrees), but it is still better than other atmospheric gases, so water is enriched with oxygen. Oxygen density under normal conditions is 1.429 g/l. At a temperature of -183 0 C and a pressure of 101.325 kPa, oxygen turns into a liquid state. Liquid oxygen has a bluish color, is drawn into a magnetic field, and at -218.7 ° C, forms blue crystals.
Natural oxygen has three isotopes O 16, O 17, O 18.
Allotropy- the ability of a chemical element to exist in the form of two or more simple substances that differ only in the number of atoms in the molecule or in structure.
Ozone O 3 – exists in the upper layers of the atmosphere at an altitude of 20-25 km from the Earth’s surface and forms the so-called “ozone layer”, which protects the Earth from the harmful ultraviolet radiation of the Sun; a pale purple, poisonous gas in large quantities with a specific, pungent but pleasant odor. The melting point is -192.7 0 C, the boiling point is 111.9 0 C. We dissolve oxygen better in water.
Ozone is a strong oxidizing agent. Its oxidative activity is based on the ability of the molecule to decompose with the release of atomic oxygen:
It oxidizes many simple and complex substances. With some metals it forms ozonides, for example potassium ozonide:
K + O 3 = KO 3
Ozone is produced in special devices - ozonizers. In them, under the influence of an electric discharge, molecular oxygen is converted into ozone:
A similar reaction occurs under the influence of lightning discharges.
The use of ozone is due to its strong oxidizing properties: it is used to bleach fabrics, disinfect drinking water, and in medicine as a disinfectant.
Inhaling ozone in large quantities is harmful: it irritates the mucous membranes of the eyes and respiratory organs.
Chemical properties.
In chemical reactions with atoms of other elements (except fluorine), oxygen exhibits exclusively oxidizing properties
The most important chemical property is the ability to form oxides with almost all elements. At the same time, oxygen reacts directly with most substances, especially when heated.
As a result of these reactions, as a rule, oxides are formed, less often peroxides:
2Ca + O 2 = 2CaO
2Ba + O 2 = 2BaO
2Na + O 2 = Na 2 O 2
Oxygen does not interact directly with halogens, gold, and platinum; their oxides are obtained indirectly. When heated, sulfur, carbon, and phosphorus burn in oxygen.
The interaction of oxygen with nitrogen begins only at a temperature of 1200 0 C or in an electrical discharge:
N 2 + O 2 = 2NO
With hydrogen, oxygen forms water:
2H 2 + O 2 = 2H 2 O
During this reaction, a significant amount of heat is released.
A mixture of two volumes of hydrogen with one volume of oxygen explodes when ignited; it is called detonating gas.
Many metals upon contact with oxygen in the air are subject to destruction - corrosion. Some metals under normal conditions are oxidized only from the surface (for example, aluminum, chromium). The resulting oxide film prevents further interaction.
4Al + 3O 2 = 2Al 2 O 3
Under certain conditions, complex substances also interact with oxygen. In this case, oxides are formed, and in some cases, oxides and simple substances.
CH 4 + 2O 2 = CO 2 + 2H 2 O
H 2 S + O 2 = 2SO 2 + 2H 2 O
4NН 3 +ЗО 2 =2N 2 +6Н 2 О
4CH 3 NH 2 + 9O 2 = 4CO 2 + 2N 2 + 10H 2 O
When interacting with complex substances, oxygen acts as an oxidizing agent. Its important property, the ability to maintain combustion substances.
Oxygen also forms a compound with hydrogen - hydrogen peroxide H 2 O 2 - a colorless transparent liquid with a pungent astringent taste, highly soluble in water. Chemically, hydrogen peroxide is a very interesting compound. Its low stability is characteristic: when standing, it slowly decomposes into water and oxygen:
H 2 O 2 = H 2 O + O 2
Light, heat, the presence of alkalis, and contact with oxidizing or reducing agents accelerate the decomposition process. The oxidation state of oxygen in hydrogen peroxide = - 1, i.e. has an intermediate value between the oxidation state of oxygen in water (-2) and in molecular oxygen (0), so hydrogen peroxide exhibits redox duality. The oxidizing properties of hydrogen peroxide are much more pronounced than the reducing properties, and they manifest themselves in acidic, alkaline and neutral environments.
H 2 O 2 + 2KI + H 2 SO 4 = K 2 SO 4 + I 2 + 2H 2 O
Hydrogen is number one in the periodic table, in groups I and VII at once. The symbol for hydrogen is H (lat. Hydrogenium). It is a very light gas, colorless and odorless. There are three isotopes of hydrogen: 1H - protium, 2H - deuterium and 3H - tritium (radioactive). Air or oxygen in reaction with simple hydrogen H₂ is highly flammable and also explosive. Hydrogen does not emit toxic products. It is soluble in ethanol and a number of metals (especially the side subgroup).
Hydrogen abundance on Earth
Like oxygen, hydrogen is of great importance. But, unlike oxygen, almost all hydrogen is bound to other substances. It is found in a free state only in the atmosphere, but its quantity there is extremely insignificant. Hydrogen is part of almost all organic compounds and living organisms. Most often it is found in the form of an oxide - water.
Physicochemical characteristics
Hydrogen is inactive, and when heated or in the presence of catalysts, it reacts with almost all simple and complex chemical elements.
Reaction of hydrogen with simple chemical elements
At elevated temperatures, hydrogen reacts with oxygen, sulfur, chlorine and nitrogen. you will learn what experiments with gases can be done at home.
Experience of interaction of hydrogen with oxygen in laboratory conditions
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Let's take pure hydrogen, which comes through the gas outlet tube, and set it on fire. It will burn with a barely noticeable flame. If you place a hydrogen tube in any vessel, it will continue to burn, and water droplets will form on the walls. This oxygen reacted with hydrogen:
2Н₂ + О₂ = 2Н₂О + Q
When hydrogen burns, a lot of thermal energy is generated. The temperature of the combination of oxygen and hydrogen reaches 2000 °C. Oxygen oxidized hydrogen, so this reaction is called an oxidation reaction.
Under normal conditions (without heating), the reaction proceeds slowly. And at temperatures above 550 ° C an explosion occurs (the so-called detonating gas is formed). In the past, hydrogen was often used in balloons, but there were many accidents due to the formation of detonating gas. The integrity of the ball was violated, and an explosion occurred: hydrogen reacted with oxygen. Therefore, helium is now used, which is periodically heated with a flame.
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Chlorine reacts with hydrogen to form hydrogen chloride (only in the presence of light and heat). The chemical reaction of hydrogen and chlorine looks like this:
H₂ + Cl₂ = 2HCl
Interesting fact: the reaction of fluorine with hydrogen causes an explosion even in darkness and temperatures below 0 ° C.
The interaction of nitrogen with hydrogen can only occur when heated and in the presence of a catalyst. This reaction produces ammonia. Reaction equation:
ЗН₂ + N₂ = 2NN₃
The reaction of sulfur and hydrogen occurs to form a gas - hydrogen sulfide. The result is a rotten egg smell:
H₂ + S = H₂S
Hydrogen not only dissolves in metals, but can also react with them. As a result, compounds are formed that are called hydrides. Some hydrides are used as fuel in rockets. They are also used to produce nuclear energy.
Reaction with complex chemical elements
For example, hydrogen with copper oxide. Let's take a tube of hydrogen and pass it through the copper oxide powder. The entire reaction occurs when heated. Black copper powder will turn brownish red (plain copper color). Droplets of liquid will also appear on the unheated areas of the flask - this has formed.
Chemical reaction:
CuO + H₂ = Cu + H₂O
As we can see, hydrogen reacted with the oxide and reduced copper.
Recovery reactions
If a substance removes an oxide during a reaction, it is a reducing agent. Using the example of the reaction of copper oxide with we see that hydrogen was a reducing agent. It also reacts with some other oxides such as HgO, MoO₃ and PbO. In any reaction, if one of the elements is an oxidizing agent, the other will be a reducing agent.
All hydrogen compounds
Hydrogen compounds with nonmetals- very volatile and poisonous gases (for example, hydrogen sulfide, silane, methane).
Hydrogen halides- Hydrogen chloride is most commonly used. When dissolved, it forms hydrochloric acid. This group also includes: hydrogen fluoride, hydrogen iodide and hydrogen bromide. All these compounds result in the formation of the corresponding acids.
Hydrogen peroxide(chemical formula H₂O₂) exhibits strong oxidizing properties.
Hydrogen hydroxides or water H₂O.
Hydrides- these are compounds with metals.
Hydroxides- these are acids, bases and other compounds that contain hydrogen.
Organic compounds: proteins, fats, lipids, hormones and others.