One of the first mineral acids, which became known to man - is sulfuric acid or sulphate.Not only she herself, but also many of its salts are used in construction, medicine, food industry and for technical purposes.Until now, in this regard, nothing has changed.A number of characteristics which has sulphate acid, make it simply irreplaceable in chemical syntheses.In addition, virtually all sectors of life and industry is the use of a salt thereof.Therefore, a closer look at what it is and what are the characteristics exhibited by the properties.
Variety
names begin with the name of the substance from a lot.Among them are those that are formed by a rational nomenclature, and those who historically.Thus, this compound is referred to as:
- acid sulphate;
- vitriol;
- sulfuric acid;
- oleum.
Although the term "oleum" not quite suited for this substance as a mixture of sulfuric acid and higher sulfur oxide - SO3.
acid sulphate: molecular formula and structure
In terms of chemical abbreviations write the formula of this acid may be because: H2SO4.It is obvious that the molecule is composed of two hydrogen cations and an anion of an acid residue - sulfate ion having a 2+ charge.
At the same within the molecule are the following links:
- polar covalent between sulfur and oxygen;
- strongly polar covalent between hydrogen and acid residue SO4.
Sulfur having 6 unpaired electrons, forming two double bonds to two oxygen atoms.More Couple - single, and those in turn - with a single hydrogen.As a result, molecular structure allows it to be strong enough.At the same time, the hydrogen cation is very mobile and easy to leave, because sulfur and oxygen much more on electronegativity.Pulling the electron density, they provide hydrogen partial positive charge, which when disconnected is complete.Since forming acidic solutions in which is H +.
Speaking of oxidation of elements in the compound, the sulfate acid formula is H2SO4, easily allows you to calculate them: one for hydrogen, oxygen at 2, at 6 sulfur.
As with any molecule, the net charge is zero.
History of discovery
acid sulphate known to the people with the most ancient times.Even the alchemists were able to get her various calcination methods sulfate.From the people received the IX century and used this substance.Later in Europe Albertus Magnus learned to extract the acid in the process of decomposition of iron sulphate.
However, none of the methods has not been profitable.Then it became known variant of the so-called Chamber of synthesis.For this burning sulfur and nitrate, and water vapor released is absorbed.As a result of acid sulphate formed.
Still later, the British were able to find the cheapest method of obtaining the substance.We used the pyrite - FeS2, iron pyrites.Calcining and subsequent reaction with oxygen still are one of the most important industrial processes for the synthesis of sulfuric acid.Such raw materials more accessible, affordable and quality for high-volume production.
physical properties
There are several options, including external, which is different from other acid sulfate.The physical properties can be described in a few paragraphs:
- Under standard conditions - fluid.
- in concentrated state is a heavy, oily, for which he became known as "oil of vitriol."
- matter density - 1.84 g / cm3.
- is colorless and odorless.
- has expressed "copper" taste.
- dissolves in water very well, almost unlimited.
- hygroscopic ability to capture both free and bound water from the tissues.
- non-volatile.
- Boiling point - 296oS.
- melting at 10,3oS.
One of the most important features of this compound is its ability to hydrate with the release of a large amount of heat.That is why from the school children are taught that to add water to the acid in any case impossible, and just the opposite.Because the density of water is lighter, so it will accumulate on the surface.If dramatically add it to the acid, the reaction dissolve out so much energy that the water starts to boil and sprayed together with the particles of hazardous substances.It can cause severe chemical burns to the skin of hands.
why should a thin stream pour acid into the water, then the mixture will overheat, but boiling does not occur, and therefore, splashing fluid, too.
chemical properties
In terms of chemistry, this acid is very strong, especially if it is a concentrated solution.It dibasic therefore dissociates stepwise to form gidrosulfat- and sulfate anion.
Overall, its interaction with various compounds complies with all the reactions characteristic of this class of substances.There are examples of a few equations, which was attended by acid sulphate.The chemical properties are manifested in its interaction with:
- salts;
- metal oxides and hydroxides;
- amphoteric oxides and hydroxides;
- metals standing in the electrochemical series before hydrogen.
As a result of such interactions in almost all cases, the average salt form of the acid (sulfates) or sour (hydrogen sulfates).
special feature is also the fact that the metals in the usual way Me + H2SO4 = MeSO4 + H2 ↑ responds only solution of this matter, that is, dilute acid.If we take a concentrated and highly saturated (oleum), the reaction products are quite different.
special properties of sulfuric acid
These include a just interaction of concentrated solutions with metals.So, there is a diagram showing the whole principle of these reactions:
- If the metal is active, the result is the formation of hydrogen sulphide, salt and water.That is, the sulfur is reduced to -2.If the metal
- average activity, the result - sulfur, salt and water.That is, the restoration of the sulfate ion to free sulfur.Metals
- low reactivity (after hydrogen) - sulfur dioxide, water and salt.The sulfur in oxidation state +4.
also special properties are acid sulphate ability to oxidize some non-metals to their highest oxidation and reacts with complex compounds and oxidize them to simple substances.
Methods for producing industrial
sulphate process for producing sulfuric acid consists of two main types:
- pin;
- tower.
Both are the most common methods in the industry worldwide.The first option is based on the use as a raw material of iron pyrites and sulfur pyrite - FeS2.In total there are three stages:
- Roasting raw materials to produce as a product of combustion of sulfur dioxide.
- Passing this gas through oxygen over a vanadium catalyst to form sulfur trioxide - SO3.
- The absorption tower is carried out dissolving the anhydride in the acid sulphate solution to form a solution of high concentration - oleum.Very heavy oily thick liquid.
second embodiment - is virtually the same, but are used as catalysts oxides of nitrogen.From the standpoint of parameters such as product quality, cost and power consumption, the purity of raw materials, productivity, the first method is more effective and acceptable, however it is frequently used.
synthesis in the laboratory
If you want to get sulfuric acid in small quantities for laboratory testing, the best way to interact with hydrogen sulfide inactive metal sulfates.
In these cases, the formation of ferrous metal sulphides, and is formed as a byproduct of sulfuric acid.For small studies that option is suitable, but the purity of this acid will not differ.
also in the laboratory can be a qualitative response to the sulfate solutions.The most common reagent is barium chloride as ion Ba2 + with sulfate anion precipitates in white precipitate - Barite milk: H2SO4 + BaCL2 = 2HCL + BaSO4 ↓
most common salt
Sulfated acid and sulfates which it forms, are importantcompounds in many industries and everyday life, including food.The most common salts of sulfuric acid are as follows:
- gypsum (alabaster, selenite).Chemical name - water, hydrated calcium sulfate.Formula: CaSO4.It used in construction, medicine, pulp and paper industry, the manufacture of jewelry.
- barite (heavy spar).Barium sulfate.The solution is a milky precipitate.In solid form - transparent crystals.It used in optical devices, X-rays, for the manufacture of an insulating coating.
- Mirabilite (Glauber's salt).Chemical name - hydrated sodium sulphate desyativodny.Formula: Na2SO4 * 10H2O.It is used in medicine as a purgative.
can cite as examples a lot of salt, which have practical significance.However, the above-mentioned - the most common.
kraft liquor
This material is a solution, which is formed as a result of heat treatment of wood, ie cellulose.The main purpose of the connection - get its sulfate soap by settling.The chemical composition of sulfate liquor following:
- lignin;
- hydroxy;
- monosaccharides;
- phenols;
- resin;
- volatile and fatty acids;
- sulfides, chlorides, carbonates and sulfates of sodium.
There are two main types of materials: white and black kraft liquor.White goes to the pulp and paper production, and black is used for the sulfate soap industry.
Main applications
annual production of sulfuric acid is 160 mln. Tons per year.This is a very significant figure, which shows the importance and prevalence of this compound.You can select multiple industries and places where you need to use a sulfate acid:
- The battery as the electrolyte, especially in the lead.
- the factories, which produces sulphate fertilizer.The bulk of this acid is a question for the manufacture of mineral supplements for plants.Therefore, plants for the production of sulfuric acid and fertilizer manufacturing often build close.
- In the food industry as an emulsifier, designated with the code E513.
- Numerous organic synthesis as a dehydrating agent, a catalyst.The obtained explosives, resins, detergents, nylon, polypropylene and ethylene, dyes, chemical fibers, esters and other compounds.
- used in filters for water purification and the manufacture of distilled water.
- Apply with mining and processing of rare elements from the ore.
also a lot of sulfuric acid is spent on laboratory tests, where it is produced by local means.
