Sulfuric acid has the formula. Sulfuric acid. Formula, properties, preparation and application. Basic physical and chemical properties of sulfuric acid
New topic: Sulfuric acid – H 2 SO 4
1. Electronic and structural formula sulfuric acid
*S - sulfur is in an excited state 1S 2 2S 2 2P 6 3S 1 3P 3 3d 2
Electronic formula of a sulfuric acid molecule:
Structural formula of the sulfuric acid molecule:
1 H - -2 O -2 O
1 H - -2 O -2 O
2.Receipt:
The chemical processes for the production of sulfuric acid can be represented as the following diagram:
S +O 2 +O 2 +H 2 O
FeS 2 SO 2 SO 3 H 2 SO 4
Sulfuric acid is prepared in three stages:
Stage 1. Sulfur, iron pyrite or hydrogen sulfide are used as raw materials.
4 FeS 2 + 11 O 2 = 2Fe 2 O 3 + 8SO 2
2 stage. Oxidation of SO 2 to SO 3 with oxygen using a V 2 O 5 catalyst
2SO 2 +O 2 =2SO 3 +Q
Stage 3. To convert SO 3 into sulfuric acid, it is not water that is used. strong heating occurs, and a concentrated solution of sulfuric acid.
SO 3 +H 2 O H 2 SO 4
The result is oleum - a solutionSO 3 in sulfuric acid.
Device circuit diagram(see textbook p. 105)
3.Physical properties.
a) liquid b) colorless c) heavy (oil of vitriol) d) non-volatile
d) when dissolved in water, strong heating occurs ( therefore, sulfuric acid must certainly be poured intowater,Anot the other way around!)
4. Chemical properties of sulfuric acid.
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DilutedH 2 SO 4 |
ConcentratedH 2 SO 4 |
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Has all the properties of acids |
Has specific properties |
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1.Changes the color of the indicator: H 2 SO 4 H + +HSO 4 - HSO 4 - H + +SO 4 2- 2. Reacts with metals standing before hydrogen: Zn+ H 2 SO 4 ZnSO 4 +H 2 3. Reacts with basic and amphoteric oxides: MgO+ H 2 SO 4 MgSO 4 +H 2 O 4. Interacts with bases (neutralization reaction) 2NaOH+H 2 SO 4 Na 2 SO 4 +2H 2 O When there is an excess of acid, acid salts are formed NaOH+H 2 SO 4 NaHSO 4 +H 2 O 5. Reacts with dry salts, displacing other acids from them (this is the strongest and most non-volatile acid): 2NaCl+H 2 SO 4 Na 2 SO 4 +2HCl 6. Reacts with salt solutions if an insoluble salt is formed: BaCl 2 +H 2 SO 4 BaSO 4 +2HCl - whitesediment qualitative reaction per ionSO 4 2- 7.When heated, it decomposes: H2SO4H2O+SO3 |
1. Concentrated H 2 SO 4 is a strong oxidizing agent; when heated, it reacts with all metals (except Au and Pt). In these reactions, depending on the activity of the metal and conditions, S,SO 2 or H 2 S is released For example: Cu+ conc 2H 2 SO 4 CuSO 4 +SO 2 +H 2 O 2.conc. H 2 SO 4 passivates iron and aluminum, therefore it can be transported in steel and aluminum tanks. 3. conc. H 2 SO 4 absorbs water well H 2 SO 4 +H 2 O H 2 SO 4 *2H 2 O Therefore, it chars organic matter |
5.Application: Sulfuric acid is one of the most important products used in various industries. Its main consumers are the production of mineral fertilizers, metallurgy, and refining of petroleum products. Sulfuric acid is used in the production of other acids, detergents, explosives, medicines, paints, as electrolytes for lead batteries. (Textbook p. 103).
6.Salts of sulfuric acid
Sulfuric acid dissociates stepwise
H 2 SO 4 H + +HSO 4 -
HSO 4 - H + +SO 4 2-
therefore, it forms two types of salts - sulfates and hydrosulfates
For example: Na 2 SO 4 - sodium sulfate (medium salt)
Na HSO 4 - sodium hydrogen sulfate (acid salt)
The most widely used are:
Na 2 SO 4 * 10H 2 O – Glauber's salt (used in the production of soda, glass, in medicine and
veterinary medicine
СaSO 4 *2H 2 O – gypsum
СuSO 4 *5H 2 O – copper sulfate (used in agriculture).
Laboratory experience
Chemical properties of sulfuric acid.
Equipment: Test tubes.
Reagents: sulfuric acid, methyl orange, zinc, magnesium oxide, sodium hydroxide and phenolphthalein, sodium carbonate, barium chloride.
b) Fill out the observation table
It has a historical name: oil of vitriol. The study of acid began in ancient times; the Greek physician Dioscorides, the Roman naturalist Pliny the Elder, the Islamic alchemists Geber, Razi and Ibn Sina, and others described it in their works. In the Sumerians there was a list of vitriols, which were classified according to the color of the substance. Nowadays, the word “vitriol” combines crystalline hydrates of divalent metal sulfates.
In the 17th century, the German-Dutch chemist Johann Glauber prepared sulfuric acid by burning sulfur with (KNO3) in the presence of In 1736, Joshua Ward (a pharmacist from London) used this method in production. This time can be considered the starting point when sulfuric acid began to be produced on a large scale. Its formula (H2SO4), as is commonly believed, was established by the Swedish chemist Berzelius (1779-1848) a little later.
Berzelius, using alphabetic symbols (indicating chemical elements) and lower digital indices (indicating the number of atoms of a given type in a molecule), established that one molecule contains 1 sulfur atom (S), 2 hydrogen atoms (H) and 4 oxygen atoms (O ). Since that time, the qualitative and quantitative composition of the molecule became known, that is, sulfuric acid was described in the language of chemistry.
Shown graphically mutual arrangement in a molecule of atoms and chemical bonds between them (they are usually designated by lines), informs that in the center of the molecule there is a sulfur atom, which is bound double bonds with two oxygen atoms. With the other two oxygen atoms, each of which has a hydrogen atom attached, the same sulfur atom is connected by single bonds.
Properties
Sulfuric acid is a slightly yellowish or colorless, viscous liquid, soluble in water at any concentration. It is a strong mineral and is highly aggressive towards metals (concentrated does not interact with iron without heating, but passivates it), rocks, animal tissues or other materials. It is characterized by high hygroscopicity and pronounced properties of a strong oxidizing agent. At a temperature of 10.4 °C, the acid solidifies. When heated to 300 °C, almost 99% of the acid loses sulfuric anhydride (SO3).
Its properties vary depending on the concentration of its aqueous solution. There are common names for acid solutions. Up to 10% acid is considered dilute. Battery - from 29 to 32%. When the concentration is less than 75% (as established in GOST 2184), it is called tower. If the concentration is 98%, then it will already be concentrated sulfuric acid. The formula (chemical or structural) remains unchanged in all cases.
When concentrated sulfuric anhydride is dissolved in sulfuric acid, oleum or fuming sulfuric acid is formed; its formula can be written as follows: H2S2O7. Pure acid (H2S2O7) is a solid with a melting point of 36 °C. The hydration reactions of sulfuric acid are characterized by the release of heat in large quantities.
Dilute acid reacts with metals, reacting with which it exhibits the properties of a strong oxidizing agent. In this case, sulfuric acid is reduced; the formula of the formed substances containing a reduced (to +4, 0 or -2) sulfur atom can be: SO2, S or H2S.
Reacts with non-metals such as carbon or sulfur:
2 H2SO4 + C → 2 SO2 + CO2 + 2 H2O
2 H2SO4 + S → 3 SO2 + 2 H2O
Reacts with sodium chloride:
H2SO4 + NaCl → NaHSO4 + HCl
It is characterized by the reaction of electrophilic substitution of a hydrogen atom attached to the benzene ring of an aromatic compound by the -SO3H group.
Receipt
In 1831, the contact method for producing H2SO4, which is currently the main one, was patented. Today, most sulfuric acid is produced using this method. The raw material used is sulfide ore (usually iron pyrite FeS2), which is fired in special furnaces, which produces a roasting gas. Since the gas temperature is 900 °C, it is cooled with sulfuric acid with a concentration of 70%. Then the gas is cleaned from dust in the cyclone and electrostatic precipitator, in washing towers with acid with a concentration of 40 and 10% of catalytic poisons (As2O5 and fluorine), and in wet electrostatic precipitators from acid aerosol. Next, the roasting gas containing 9% sulfur dioxide (SO2) is dried and fed into the contact apparatus. After passing through 3 layers of vanadium catalyst, SO2 is oxidized to SO3. Concentrated sulfuric acid is used to dissolve the resulting sulfuric anhydride. The formula for a solution of sulfuric anhydride (SO3) in anhydrous sulfuric acid is H2S2O7. In this form, oleum is transported in steel tanks to the consumer, where it is diluted to the desired concentration.
Application
Due to its different chemical properties, H2SO4 has a wide range of applications. In the production of the acid itself, as an electrolyte in lead-acid batteries, for the manufacture of various cleaning products, it is also an important reagent in the chemical industry. It is also used in the production of: alcohols, plastics, dyes, rubber, ether, adhesives, soaps and detergents, pharmaceutical products, pulp and paper, petroleum products.
Any acid is a complex substance whose molecule contains one or more hydrogen atoms and an acid residue.
The formula of sulfuric acid is H2SO4. Consequently, the sulfuric acid molecule contains two hydrogen atoms and the acidic residue SO4.
Sulfuric acid is formed when sulfur oxide reacts with water
SO3+H2O -> H2SO4
Pure 100% sulfuric acid (monohydrate) is a heavy liquid, viscous like oil, colorless and odorless, with a sour “copper” taste. Already at a temperature of +10 ° C it hardens and turns into a crystalline mass.
Concentrated sulfuric acid contains approximately 95% H2SO4. And it hardens at temperatures below –20°C.
Interaction with water
Sulfuric acid dissolves well in water, mixing with it in any proportion. This releases a large amount of heat.
Sulfuric acid can absorb water vapor from the air. This property is used in industry for drying gases. The gases are dried by passing them through special containers with sulfuric acid. Of course, this method can only be used for those gases that do not react with it.
It is known that when sulfuric acid comes into contact with many organic substances, especially carbohydrates, these substances become charred. The fact is that carbohydrates, like water, contain both hydrogen and oxygen. Sulfuric acid takes these elements away from them. What remains is coal.
IN aqueous solution H2SO4 indicators litmus and methyl orange turn red, which indicates that this solution has a sour taste.
Interaction with metals
Like any other acid, sulfuric acid is capable of replacing hydrogen atoms with metal atoms in its molecule. It interacts with almost all metals.
Diluted sulfuric acid reacts with metals like an ordinary acid. As a result of the reaction, a salt with an acidic residue SO4 and hydrogen is formed.
Zn + H2SO4 = ZnSO4 + H2
A concentrated sulfuric acid is a very strong oxidizing agent. It oxidizes all metals, regardless of their position in the voltage series. And when reacting with metals, it itself is reduced to SO2. Hydrogen is not released.
Сu + 2 H2SO4 (conc) = CuSO4 + SO2 + 2H2O
Zn + 2 H2SO4 (conc) = ZnSO4 + SO2 + 2H2O
But gold, iron, aluminum, and platinum group metals do not oxidize in sulfuric acid. Therefore, sulfuric acid is transported in steel tanks.
The sulfuric acid salts that are obtained as a result of such reactions are called sulfates. They are colorless and easily crystallize. Some of them are highly soluble in water. Only CaSO4 and PbSO4 are slightly soluble. BaSO4 is almost insoluble in water.
Interaction with bases
The reaction between acids and bases is called neutralization reaction. As a result of the neutralization reaction of sulfuric acid, a salt containing the acid residue SO4 and water H2O are formed.
Examples of sulfuric acid neutralization reactions:
H2SO4 + 2 NaOH = Na2SO4 + 2 H2O
H2SO4 + CaOH = CaSO4 + 2 H2O
Sulfuric acid reacts with neutralization with both soluble and insoluble bases.
Since the sulfuric acid molecule has two hydrogen atoms, and two bases are required to neutralize it, it is classified as a dibasic acid.
Interaction with basic oxides
From school course chemistry we know that oxides are called complex substances, which includes two chemical element, one of which is oxygen in the oxidation state -2. Basic oxides are called oxides of 1, 2 and some 3 valence metals. Examples of basic oxides: Li2O, Na2O, CuO, Ag2O, MgO, CaO, FeO, NiO.
Sulfuric acid reacts with basic oxides in a neutralization reaction. As a result of this reaction, as in the reaction with bases, salt and water are formed. The salt contains the acidic residue SO4.
CuO + H2SO4 = CuSO4 + H2O
Interaction with salts
Sulfuric acid reacts with salts of weaker or volatile acids, displacing these acids from them. As a result of this reaction, a salt with an acidic residue SO4 and an acid are formed
H2SO4+BaCl2=BaSO4+2HCl
Application of sulfuric acid and its compounds
Barium porridge BaSO4 is capable of blocking X-rays. Filling hollow organs with it human body, radiologists examine them.
In medicine and construction, natural gypsum CaSO4 * 2H2O and calcium sulfate crystalline hydrate are widely used. Glauber's salt Na2SO4 * 10H2O is used in medicine and veterinary medicine, in the chemical industry - for the production of soda and glass. Copper sulfate CuSO4 * 5H2O is known to gardeners and agronomists, who use it to combat pests and plant diseases.
Sulfuric acid is widely used in various industries: chemical, metalworking, oil, textile, leather and others.
Undiluted sulfuric acid is a covalent compound.
In the molecule, sulfuric acid is tetrahedrally surrounded by four oxygen atoms, two of which are part of the hydroxyl groups. The S–O bonds are double, and the S–OH bonds are single.
The colorless, ice-like crystals have a layered structure: each H 2 SO 4 molecule is connected to four neighboring strong hydrogen bonds, forming a single spatial framework.
The structure of liquid sulfuric acid is similar to the structure of solid one, only the integrity of the spatial framework is broken.
Physical properties of sulfuric acid
Under normal conditions, sulfuric acid is a heavy, oily liquid without color or odor. In technology, sulfuric acid is a mixture of both water and sulfuric anhydride. If the molar ratio of SO 3: H 2 O is less than 1, then it is an aqueous solution of sulfuric acid; if it is greater than 1, it is a solution of SO 3 in sulfuric acid.
100% H 2 SO 4 crystallizes at 10.45 ° C; T kip = 296.2 °C; density 1.98 g/cm3. H 2 SO 4 mixes with H 2 O and SO 3 in any ratio to form hydrates; the heat of hydration is so high that the mixture can boil, splash and cause burns. Therefore, it is necessary to add acid to water, and not vice versa, since when water is added to acid, lighter water will end up on the surface of the acid, where all the heat generated will be concentrated.
When aqueous solutions of sulfuric acid containing up to 70% H 2 SO 4 are heated and boiled, only water vapor is released into the vapor phase. Sulfuric acid vapor also appears above more concentrated solutions.
In terms of structural features and anomalies, liquid sulfuric acid is similar to water. There is the same system of hydrogen bonds, almost the same spatial framework.
Chemical properties of sulfuric acid
Sulfuric acid is one of the strongest mineral acids; due to its high polarity, the H–O bond is easily broken.
Sulfuric acid dissociates in aqueous solution , forming a hydrogen ion and an acidic residue:
H 2 SO 4 = H + + HSO 4 - ;
HSO 4 - = H + + SO 4 2- .
Summary equation:
H 2 SO 4 = 2H + + SO 4 2- .
Shows properties of acids , reacts with metals, metal oxides, bases and salts.
Dilute sulfuric acid does not exhibit oxidizing properties; when it interacts with metals, hydrogen and a salt containing the metal in the lowest oxidation state are released. In the cold, the acid is inert towards metals such as iron, aluminum and even barium.
Concentrated acid has oxidizing properties. Possible interaction products simple substances with concentrated sulfuric acid are given in the table. The dependence of the reduction product on the acid concentration and the degree of activity of the metal is shown: the more active the metal, the more deeply it reduces the sulfate ion of sulfuric acid.
Interaction with oxides:
CaO + H 2 SO 4 = CaSO 4 = H 2 O.
Interaction with bases:
2NaOH + H 2 SO 4 = Na 2 SO 4 + 2H 2 O.
Interaction with salts:
Na 2 CO 3 + H 2 SO 4 = Na 2 SO 4 + CO 2 + H 2 O.
Oxidative properties
Sulfuric acid oxidizes HI and HBr to free halogens:
H 2 SO 4 + 2HI = I 2 + 2H 2 O + SO 2.
Sulfuric acid takes away chemically bound water from organic compounds containing hydroxyl groups. Dehydration of ethyl alcohol in the presence of concentrated sulfuric acid leads to the production of ethylene:
C 2 H 5 OH = C 2 H 4 + H 2 O.
The charring of sugar, cellulose, starch and other carbohydrates upon contact with sulfuric acid is also explained by their dehydration:
C 6 H 12 O 6 + 12H 2 SO 4 = 18H 2 O + 12SO 2 + 6CO 2.
Acids are chemical compounds, consisting of hydrogen atoms and acidic residues, for example, SO4, SO3, PO4, etc. They are inorganic and organic. The first include hydrochloric, phosphoric, sulfide, nitric, and sulfuric acid. The second ones include acetic acid, palmitic acid, formic acid, stearic acid, etc.
What is sulfuric acid
This acid consists of two hydrogen atoms and the acidic residue SO4. It has the formula H2SO4.
Sulfuric acid or, as it is also called, sulfate acid, refers to inorganic oxygen-containing dibasic acids. This substance is considered one of the most aggressive and chemically active. In most chemical reactions it acts as an oxidizing agent. This acid can be used in concentrated or dilute form, in these two cases it has slightly different Chemical properties.
Physical properties
Sulfuric acid under normal conditions has liquid state, its boiling point is approximately 279.6 degrees Celsius, its freezing point, when it turns into solid crystals, is about -10 degrees for one hundred percent and about -20 for 95 percent.
Pure one hundred percent sulfate acid is an odorless, colorless, oily liquid substance that has almost twice the density of water - 1840 kg/m3.
Chemical properties of sulfate acid
Sulfuric acid reacts with metals, their oxides, hydroxides and salts. Diluted with water in different proportions, it can behave differently, so let’s take a closer look at the properties of concentrated and weak solutions of sulfuric acid separately.
Concentrated sulfuric acid solution
A solution containing at least 90 percent sulfate acid is considered concentrated. Such a solution of sulfuric acid is capable of reacting even with low-active metals, as well as non-metals, hydroxides, oxides, and salts. The properties of such a solution of sulfate acid are similar to those of concentrated nitrate acid.
Interaction with metals
During the chemical reaction of a concentrated solution of sulfate acid with metals located to the right of hydrogen in the electrochemical voltage series of metals (that is, with not the most active ones), the following substances are formed: sulfate of the metal with which the interaction occurs, water and sulfur dioxide. Metals, as a result of interaction with which the listed substances are formed, include copper (cuprum), mercury, bismuth, silver (argentum), platinum and gold (aurum).
Interaction with inactive metals
With metals that are to the left of hydrogen in the voltage series, concentrated sulfuric acid behaves slightly differently. As a result of this chemical reaction, the following substances are formed: sulfate of a certain metal, hydrogen sulfide or pure sulfur and water. The metals with which a similar reaction occurs also include iron (ferum), magnesium, manganese, beryllium, lithium, barium, calcium and all others that are in the voltage series to the left of hydrogen, except aluminum, chromium, nickel and titanium - with them concentrated sulfate acid does not interact.
Interaction with non-metals
This substance is a strong oxidizing agent, so it is capable of participating in redox chemical reactions with non-metals, such as, for example, carbon (carbon) and sulfur. As a result of such reactions, water is necessarily released. When this substance is added to carbon, carbon dioxide and sulfur dioxide are also released. And if you add acid to sulfur, you get only sulfur dioxide and water. In such a chemical reaction, sulfate acid plays the role of an oxidizing agent.
Interaction with organic substances
Among the reactions of sulfuric acid with organic substances, charring can be distinguished. This process occurs when this substance collides with paper, sugar, fibers, wood, etc. In this case, carbon is released in any case. The carbon formed during the reaction can partially react with sulfuric acid if it is in excess. The photo shows the reaction of sugar with a solution of sulfate acid of medium concentration.
Reactions with salts
Also, a concentrated solution of H2SO4 reacts with dry salts. In this case, a standard exchange reaction occurs, in which the metal sulfate that was present in the salt structure and the acid with the residue that was in the salt are formed. However, concentrated sulfuric acid does not react with salt solutions.
Interaction with other substances
Also, this substance can react with metal oxides and their hydroxides, in these cases exchange reactions occur, in the first, metal sulfate and water are released, in the second - the same.
Chemical properties of a weak solution of sulfate acid
Dilute sulfuric acid reacts with many substances and has the same properties as all acids. It, unlike concentrated metal, interacts only with active metals, that is, those that are to the left of hydrogen in the voltage series. In this case, the same substitution reaction occurs as in the case of any acid. This releases hydrogen. Also, such an acid solution interacts with salt solutions, resulting in an exchange reaction, already discussed above, with oxides - the same as a concentrated one, with hydroxides - also the same. In addition to ordinary sulfates, there are also hydrosulfates, which are the product of the interaction of hydroxide and sulfuric acid.
How to tell if a solution contains sulfuric acid or sulfates
To determine whether these substances are present in a solution, a special qualitative reaction to sulfate ions is used, which makes it possible to find out. It consists of adding barium or its compounds to the solution. This may result in precipitation white(barium sulfate), which indicates the presence of sulfates or sulfuric acid.
How is sulfuric acid produced?
The most common way industrial production This substance is extracted from iron pyrite. This process occurs in three stages, at each of which a certain chemical reaction. Let's look at them. First, oxygen is added to pyrite, resulting in the formation of ferum oxide and sulfur dioxide, which is used for further reactions. This interaction occurs at high temperature. Next comes the stage in which sulfur trioxide is obtained by adding oxygen in the presence of a catalyst, which is vanadium oxide. Now, at the last stage, water is added to the resulting substance, and sulfate acid is obtained. This is the most common process for the industrial extraction of sulfate acid, it is used most often because pyrite is the most accessible raw material suitable for the synthesis of the substance described in this article. Sulfuric acid obtained through this process is used in various fields of industry - both in the chemical and in many others, for example, in oil refining, ore dressing, etc. Its use is also often provided for in the manufacturing technology of many synthetic fibers .