Water soluble fertilizers. Obtaining phosphoric acid in industry

According to the degree of solubility, phosphate fertilizers are divided into three groups:

1. water soluble available for all kinds of plants. Monosubstituted phosphates: Ca (H 2 Po 4) 2, Mg (H 2 Po 4) 2, K 2 H 2 PO 4, NaH 2 PO 4, NH 4 H 2 PO 4 and other various types of superphosphates.
2. Insoluble in water, but soluble in weak acids(for example, lemon) or in alkaline-lemon solutions - disubstituted phosphates: CaHPO 4, MgHPO 4 (partially available for feeding plants-precipitates, etc.).
3. Insoluble in water and weak acids- trisubstituted: Ca 3 (Po 4) 2, Mg 3 (PO 4) 2. Hard-to-reach for plants is phosphate rock. Partially it can be used by crops whose root system is capable of secreting weak organic acids (buckwheat, mustard, lupine, peas).

The coefficient of phosphorus assimilation is very low (15-30%) due to the rapid conversion of the introduced soluble phosphorus into phosphates that are inaccessible to plants. Therefore, to increase the content of mobile phosphates in the soil, on sandy and sandy soils, it is recommended to add P40-60, for light loamy and medium loamy soil - P60-90 and heavy loamy - P90-120.

Superphosphate granulated

Ca (H 2 PO 4) 2 -H 2 O + H 3 PO 4 +2 CaS0 4 (Brand - P20 S11 Ca30)

Superphosphate granulated is a physiologically acidic, water-soluble phosphate fertilizer. Contains more than 30% calcium sulfate, which is of practical importance as a source of sulfur (11%). It is used for the main and pre-sowing application in fertilizer systems in all soil and climatic zones of Russia, for all crops. It is characterized by slow and uniform release of batteries. The composition of the fertilizer includes trace elements: B, Cu, Mn, Mo, Zn. Valuable fertilizer for cruciferous crops (rapeseed, etc.) and legumes.

Superphosphate ammoniated granular

NH 4 H 2 PO 4 + Ca (H 2 PO 4) 2 x H 2 O + CaSO 4 + H 3 PO 4 - Grade N3: P17: S12

It is used in fertilizer systems in all soil and climatic zones of Russia. In addition to 3% nitrogen and 17% phosphorus, it contains 12% sulfur (40-55% calcium sulfate CaSO4), which is especially valuable on soils where it is necessary to additionally include sulfur-containing fertilizers in the fertilizer system. It is better to use for legumes, cruciferous oilseeds that are demanding on sulfur nutrition.

Fertilizer application rates are calculated based on the results of agrochemical analyzes of the soil, climatic conditions, biological needs and expected yields. The optimal rate of ammoniated superphosphate for winter wheat is 3-6 q/1ha, for sugar beet - 5-8 q/1ha. The best way to apply is on the stubble before plowing.

Granular ammonized superphosphate is a chemically acidic, water-soluble fertilizer. Due to the neutralization of the acidic action by ammonia, it does not oxidize the soil, unlike superphosphate. It has a minimum of 10% higher efficiency compared to traditional superphosphate.

Phosphorus flour

Ca 3 (Po 4) 2 x CaCO 3 (P18-20 Ca34)

Phosphorus flour contains trisubstituted phosphorus in the form of Ca 3 (Po 4) 2 , we will not dissolve in water, but only in weak acids. Of great importance in improving the efficiency of phosphate rock is the degree of grinding. The smaller the better. Allowed the remainder of the particles that do not pass through the holes of the sieve with a diameter of 0.18 mm, not more than 10%.

Phosphorus in fertilizer is in a hard-to-reach form. Its effectiveness increases on acidic soils with pH=5.6 and below.

The availability of phosphorus from flour for most crops is low. It is absorbed only by cultures whose root system has acid secretions, namely: lupine, buckwheat, mustard. Cereal crops poorly absorb phosphorus from this fertilizer.

The effectiveness of phosphorus flour increases significantly when composted with organic fertilizers. It promotes the transfer of phosphorus into accessible forms of sowing, especially white mustard, which absorbs it well. The next crop already uses phosphorus, which is released during the decomposition of biomass.

The application rate of phosphorus flour for the main cultivation is 5-20 centners / 1 ha once every 5-6 years to provide the soil with phosphorus and especially calcium. This fertilizer is, first of all, a good ameliorator for radical improvement of the soil, in particular, it reduces its acidity.

In such fertilizers as nitrophos and nitrophoska, more than half of the phosphorus is in a hard-to-reach state. Therefore, it is advisable to apply them on acidic soils in the main fertilizer (for plowing).

Phosphorus fertilizers(chem.-tech.). - Fertilizers are called various substances of natural origin or artificially prepared, containing as the main one of the most valuable component for plant culture - phosphorus in the form of compounds that are more or less easily assimilated by plants. Such compounds are salts of phosphoric acid, soluble in water already in the finished commercial product or easily formed in it under the influence of various chemical processes occurring with it in the soil. F. fertilizers, along with phosphorus, usually contain other components that play an important role in plant life, such as nitrogen, sulfur, potassium, etc. Of the most famous and applicable F. fertilizers, guano (see), bone flour (see Bones), flour from animal meat, fish, horns, superphosphates, thomas slag flour, etc. In this article, we will consider the preparation of superphosphates and thomas slag flour, and then methods for the chemical analysis of various F. fertilizers. Regarding the role of F. fertilizers in the soil - see the Doctrine of fertilizer.

Superphosphates. The main component of superphosphates is the water-soluble acid phosphorus-calcium salt Ca (H 2 PO 4) 2, obtained together with gypsum CaSO 4 by the action of sulfuric acid on the average phosphorus-lime salt Ca 3 (PO 4) 2, for example:

Ca 3 (PO 4) 2 + 2H 2 SO 4 \u003d Ca (H 2 PO 4) 2 + CaSO 4.

To obtain superphosphate, all substances rich in phosphorus-lime salt can be used; in technology, when choosing a material for the manufacture of superphosphate, much attention is paid to the presence in it of some other compounds that can play an unfavorable role for production. Such compounds are mainly CaCO 3 carbon-lime salt, often found together with Ca 3 (PO 4) 2, and iron and aluminum oxides (Fe 2 O 3 and Al 2 O 3). Carbon-lime salt under the action of sulfuric acid decomposes according to the equation:

CaCO 3 + H 2 SO 4 \u003d CaSO 4 + CO 2 + H 2 O,

releasing carbon dioxide and passing into gypsum, and, thus, part of the sulfuric acid is spent unproductively. Iron and aluminum oxides are harmful in the sense that during storage of superphosphate they gradually act on the water-soluble acid phosphorus-lime salt Ca (H 2 PO 4) 2 and convert it into an insoluble CaHPO 4 salt, for example:

2Ca (H 2 PO 4) 3 + Fe 2 O 3 \u003d 2CaHRO 4 + 2FePO 4 + 3H 2 O,

and the value of the product goes down. Raw materials used for the preparation of superphosphate are divided into two large groups: I) artificial products and garbage other industries; these include: bone meal, bone charcoal, bone ash; II) natural phosphates: coprolites, phosphorites, phosphate guano, etc. Regarding bone meal, see Bones. Bone char is obtained chiefly from sugar refineries, after it ceases to act to decolourize sugar solutions; some of it comes from the bone-burning factories as waste (fines) when crushing and sorting bone charcoal for sugar factories. The longer bone charcoal is used in a sugar factory, the more often it contains more carbon-lime salt and less phosphoric acid, which is lost during the "revitalization" of coal; in particular, it is small (up to 25% Ca 3 (RO 4) 2 and less) in coal dust, which is carried away in the form of dirt by water when washing coal and is collected and settled in special tanks in well-maintained factories. Very often bone char is adulterated by the addition of sand, and sometimes it does not contain phosphoric acid at all and is nothing more than the residue from the distillation of bituminous slates; therefore, when accepting bone charcoal to the superphosphate plant, it must certainly be examined. In good bone charcoal, there is 65-70% calcium phosphate (which corresponds to 30.5-33% phosphoric acid, P 2 O 5), 10% calcium carbonate and the same amount of water; the rest consists of sand and coal. Bone ash comes mainly from America, where a huge number of cattle beat on the prairies and the bones serve as a combustible material. Bone ash is richer in phosphorus than bone charcoal (75-80% Ca 3 (PO 4) 2 and 5-6% CaCO 3). The main mass of superphosphate is prepared from natural phosphates. The operation of preparing superphosphate is very simple. First of all, the material intended for production is crushed, whereby porous substances, such as bone char or ash, which are easily impregnated with sulfuric acid, are crushed to a size mustard grains; Baker-guano is sifted and ground; all hard, dense materials must be reduced to powder. For this purpose, they are first roughly broken and then ground in mills; the most suitable are ball mills. In FIG. 1 and 2 shows one of them in two sections.

It consists of a strong shaft w and a drum formed by 8 lattices A 1, A 2 ..., on which heavy cast-iron balls of various sizes lie. Lattices rotate somewhat in trunnions a and its edges b, c rest on special grooved protrusions, which are interconnected from the outside by sheet iron with many holes g; there is a canvas on it. This is where sifting takes place. Shaft W driven by a machine with pulleys d, d 1 and gear ef. The grinding material is fed through the funnel E; fine dust passes through grates and sieve and is collected in a drawer M; unsifted flour from the movement of the bars again falls into the drum and is rubbed with cast-iron balls. Grinding must be very thorough, since when treated with sulfuric acid, large particles of phosphate are enveloped in gypsum, which stops the access of acid into the grain. The crushed material is then treated with sulfuric acid. Sulfuric acid is usually taken diluted, the so-called. chamber acid 53 ° B., beats. in. 1.580; the water in it partly evaporates during the decomposition of phosphate, partly joins the gypsum, and therefore, after treatment with acid, a completely dry product is usually obtained. Sometimes sulfuric acid is taken as waste from other industries, for example. from the preparation of nitrobenzene, nitrocellulose, purification of solar oils. The amount of sulfuric acid is calculated on the basis of an analysis of the material, taking into account, in addition to calcium phosphate, and calcium carbonate. Often the material going to superphosphate contains a lot of water; to obtain a dry product, as required by practice, this water is taken into account; the material is pre-dried, or, even simpler, a stronger acid is taken for decomposition. Mixing with sulfuric acid is done in various ways. In small production, wooden vats lined with lead inside serve for this purpose. Having poured the proper amount of sulfuric acid, the mass is stirred with an oar or an iron poker; a very energetic reaction occurs, accompanied by the release of carbon dioxide and a large amount of heat. The mass, at first almost liquid, begins to thicken gradually and, finally, completely hardens; it is then taken out, piled up to cool, and then broken up and sieved. Instead of wooden vats, some factories set up shallow stone tanks in the ground, which can be easily loaded and unloaded with wheelbarrows. The tank is closed from above with a lid, in which there is an opening leading to the exhaust pipe; working gases harmful to health, such as, for example, hydrogen fluoride, hydrogen chloride, etc., enter it. From the mechanical devices used to decompose phosphates with sulfuric acid, a rather simple apparatus is shown in Fig. 3.

It consists of a flat cylindrical closed tank AND, in which the shaft rotates D with two crossbars AT, equipped with blades reaching the bottom FROM, pipe E serves to remove gases formed during decomposition. It leads to a chimney, and the exhaust gases are sometimes washed with water to retain acid fumes. When the decomposition is over, a shutter opens at the bottom of the apparatus and its contents are dumped into a trolley standing below and transported to the warehouses. In large plants, the decomposition of phosphates is carried out in continuously operating apparatuses, the example of which is shown in Fig. four.

It consists of an inclined tube in which a helical agitator rotates. The materials to be mixed enter the top of the pipe and exit at the other end. After hardening, superphosphate is subjected to grinding. The easiest way to turn into superphosphate is bone charcoal; when using bone meal, they often strive to get a product rich in nitrogen; for this, crushed horn, leather, etc. are added to the finished superphosphate. Instead of organic nitrogenous substances, ammonium salts are added to superphosphate - mainly ammonium sulphate (they make sure that it does not contain rhodanide salts harmful to vegetation) or chilean saltpeter. Easily converted into superphosphates and various kinds of phosphate guano, for example. Baker-guano; with a high water content, they have to be dried. The most difficult operation is with phosphorites. In the manufacture of superphosphates, it is necessary to strive to ensure that, if possible, all the phosphorus-lime salt is converted into an acid salt; the fact is that the average salt Ca 3 (RO 4) 2 gradually converts the acid salt into an insoluble state:

Ca (RO 4) 2 + Ca 3 (RO 4) 2 \u003d 4CaHPO 4.

Entitled double superphosphate a product is known in the art, prepared by the action of free phosphoric acid on phosphate guano and other phosphorus-rich materials, containing up to 42% of phosphoric acid, soluble in water. The interest of production lies in the fact that phosphoric acid itself is prepared from materials unsuitable for conversion into superphosphate. Finely ground phosphorite is mixed with dilute 20% sulfuric acid, taken in such an amount as is required to isolate all the phosphoric acid in the free state by the reaction of Ca 3 (PO 4) 2 + 3H 2 SO 4 \u003d 2H 3 PO 4 + 3CaSO 4, taking , of course, in the calculation and calcium carbonate. The acid is taken as weak, because such an acid has little effect on phosphorus-iron salts. The decomposition of phosphorite is carried out in large wooden vats equipped with a stirrer. When decomposed up to 2000 kilos. phosphorite temp. rises to 50-60 °; after two hours, decomposition almost ends, and 1-2% phosphoric acid that has not passed into the solution remains; the liquid, together with the residue, is lowered into another vat with a stirrer, allowed to cool to 35 ° and then filtered; the residue not dissolved in sulfuric acid is collected on a filter and washed with water. Wash waters rich in phosphoric acid (up to 5%) are added to the filtrate, and the rest goes to dilute the sulfuric acid. The remainder, containing 1-3% phosphoric acid, goes on sale under the name superphosphate-gypsum. The filtrate contains from 7 to 10% P 2 O 5 ; it is subjected to evaporation in flat vats until it thickens to 56 ° B., which corresponds to a content of 50% P 2 O 5; it is then poured into special tanks where it is cooled. A solution of phosphoric acid is mixed with phosphates rich in phosphoric acid in mixers in such a proportion as to convert Ca 3 (PO 4) 2 into a soluble acid salt according to the equation:

Ca C (PO 4) 2 + 4H C PO 4 \u003d 3Ca (H 2 PO 4) 2.

After 12 hours, when the mass thickens strongly, it is taken out of the mixer, dried for several days at 80° - 100° in a stream of heated air and crushed in disintegrators.

Thomas slag flour. When processing iron ores rich in phosphorus, as is known, thomasing (the Thomas method) is used, consisting in the fact that the pig iron obtained in the blast furnace is melted and blown in Bessemer converters with a dolomite heel with an addition of lime, and all the phosphorus of the pig iron passes into slag. Fresh Thomas slag is a solid bubbly mass with crystalline inclusions. The following table gives the concept of the composition of slags:

Numerous studies indicate that phosphoric acid is found in Thomas slags, mainly in the form of the compound Ca 4 P 2 O 9, the basic salt of phosphoric acid Ca 3 (PO 4) 2 CaO, or, perhaps, the salt of an unknown diphosphoric acid (HO) 8 P 2 O. The significant content of phosphoric acid in the slag, which was worthless waste in metallurgical plants, gave the idea to use the slag for fertilizer. It was inconvenient to use thomas slags for processing into superphosphate due to the high content of iron in them, but this soon turned out to be unnecessary, since experiments showed that phosphoric acid in slags is in such a compound that easily decomposes in the soil with carbon dioxide from the air and water, and phosphoric acid becomes soluble. The only treatment that thomas slags are most often subjected to is that they are crushed so that they can be better mixed with the soil. The slags are first roughly crushed, then carefully ground in ball mills. It is believed that it is more convenient to take slags that have already lain down for a year.

Analysis of F. fertilizers. In the study of F. fertilizers, the content of the following components is mainly determined in them: phosphorus, nitrogen, iron, aluminum, potassium, water and ash, and sometimes also carbon dioxide, fluorine, etc. Phosphorus, which is the main component of F. fertilizers, is located in them, mainly in the form of calcareous salts of phosphoric acid. 4 types of Ca (H 2 PO 4) 2, CaHRO 4, Ca 3 (RO 4) 2 and Ca 3 (RO 4) 2 ∙CaO; in addition, they may contain phosphate salts of aluminum, iron, ammonium, potassium, etc. Since a greater or lesser degree of absorption of phosphorus by plants depends on the properties of those compounds in the form of which it is found in the soil, a well-known classification of phosphate salts has been developed in practice found in fertilizers. Distinguish "phosphoric acid, soluble in water" - that acid, which is in the form of salts soluble in water, for example. acid phosphorus-lime salt Ca (H 2 PO 4) 2, alkaline phosphate salts, etc.; all other phosphoric acid is called "insoluble phosphoric acid". Water-insoluble phosphate salts, e.g. CaHRO 4, Ca 3 (RO 4) 2 ∙CaO, Ca 3 (RO 4) 2 differ from each other in relation to ammonium citrate and citric acid. The calcium salt of the CaHPO 4 composition, which is formed, as indicated above, in superphosphates from the acid salt of Ca (H 2 PO 4) 2 under the action of iron and aluminum oxide and thus characterizes its change over time, easily dissolves in an aqueous solution of ammonium citrate, and hence the phosphoric acid in this salt (and similar ones) is called "phosphoric acid soluble in citrate salt (citralösliche)". The salt of the composition Ca 3 (RO 4) 2 ∙CaO, very characteristic of fertilizers obtained from Tomas slags, dissolves in a weak aqueous solution of ammonium citrate, as well as in dilute citric acid; thanks to this, "phosphoric acid, soluble in citric acid" is distinguished. (Citronensäurelösliche)". The average calcium salt Ca 3 (PO 4) 2 and similar salts of aluminum and iron do not dissolve under the above conditions. When analyzing the F. of fertilizers, the total content of phosphoric acid in them is sometimes determined. Nitrogen in F. fertilizers is in the form of nitrogenous organic compounds, in the form of salts of nitric acid, and in the form of ammonium salts. Regarding its definition, see the article Nitrometry. In general, nothing special can be said about the definition of the remaining components of the F. of fertilizers. Let us consider in succession the methods of analysis of various circulating in the practice of F. fertilizers. The result of the analysis, as in general with all technical analyzes, is determined, firstly, by how the sample of the material under study is taken or composed, and secondly, by what method of determination was used. With regard to the preparation of a sample for analysis, all the usual general rules are observed here, which make it possible to obtain really middle sample of the studied material; after appropriate sampling, solids must be crushed and mixed by sieving, soft ones are mixed by hand; when sending and storing the sample, precautions should be taken against the loss of volatile substances (water, etc.) and any other changes, etc. The choice of the determination method depends on whether it is required to obtain an approximate result from the chemist (with known and sufficient accuracy for practice) and possibly fast or possibly exact solution of a given problem is required, where the time required for work plays a secondary role.

Superphosphate. For determining humidity take a sample of 10 gr. and dried for 3 hours at 100°. For determining phosphoric sour, soluble in water, superphosphate is extracted with water. To do this, put a sample of 20 gr. into a liter flask, pour 800 kb. cm of water and shake vigorously for 30 minutes; the latter is usually done mechanically, with the help of special rotating apparatus. After shaking, the liquid is added with water up to a liter, vigorously shaken and filtered. Usually 50 kb are taken from the resulting clear solution. cm (corresponding to 1 g of the sample taken) and the content of phosphoric acid is determined here by weight or volume. Of the more accelerated methods, which, however, give good results, the following is used quite often. It consists in the fact that phosphoric acid is precipitated magnesia mixture in the presence of lemon-ammonia salt. Precipitation is very fast; a certain amount of lime, alumina, and iron then precipitates, but at the same time a certain amount of phosphoric acid remains in solution, so that one is compensated for by the other, and the results are very tolerable. The amount of phosphoric acid extracted from superphosphate is calculated from the weight of the obtained pyrophosphorus-magnesian salt Mg 2 P 2 O 7 . The solution of lemon-ammonia salt used in the determination is prepared by dissolving 110 g. chemically pure citric acid in water, adding 400 kb here. cm 24% ammonia and diluting it all to 1 liter with water; magnesian mixture is obtained by dissolving 55 gr. magnesium chloride MgCl 2, 105 gr. ammonia NH 4 Cl in 650 kb. cm of water and 350 kb. cm 24% ammonia. When analyzing - to the above 50 kb. cm water extract of superphosphate is poured 50 kb. see lemon-ammonia solution; in this case, a non-disappearing precipitate should not form; if it is, then add more ammonium citrate until the precipitate dissolves; then pour 25 kb here. cm magnesia mixture and shaken for about 1/2 hour (according to some, 10 minutes is enough). The precipitate of the obtained phosphorus-ammonium-magnesian salt is collected on a weighed asbestos filter in a platinum crucible with a perforated bottom, washed with 5% ammonia by suction, dried, calcined and weighed. The crucible is put back into action (up to 40 times) without changing the asbestos. The preparation of a new asbestos filter requires great care. Fibrous asbestos is taken, carefully split with a knife on a glass plate, boiled for 2 hours in strong hydrochloric acid and then washed many times in a large glass with water, which at the same time carries away small hairs of asbestos. To prepare a filter, asbestos is stirred up in water, poured into a crucible, the water is sucked off, it is compacted with a glass rod so that it lies evenly and fits snugly against the walls, washed with water, dried, calcined and weighed. The most accurate method for determining phosphoric acid is to separate it using molybdenum liquid and then converting it into a pyrophosphorus magnesia salt. Of the many methods proposed for this purpose, we indicate the following. Cooking molybdenum liquid, dissolving 50 gr. molybdic acid in a mixture of 100 kb. cm of water and 100 kb. cm ammonia (sp. w. 0.91), the solution is gradually poured into 800 kb. see diluted nitric acid. (200 kb. cm of nitric acid. beats. in. 1.4 and 600 kb. cm of water); then prepare a magnesia mixture, dissolving 55 gr. MgCl 2 and 70 gr. NH 4 Cl in water, pour 350 kb. see ammonia sp. in. 0.97 and diluted with water to 1 liter. When analyzing, they are taken into a glass or into an Erlenmeyer flask with a capacity of 300 k.s. 25 or 50 kb. cm of the investigated liquid so that it contains up to 0.1-0.2 g. phosphoric acid., and molybdenum liquid is poured here (according to the calculation for each 0.1 g of phosphoric acid, about 100 k.s.); a yellow precipitate of phosphomolybdic acid is immediately formed; the liquid is heated for 4-6 hours. in a water bath at 60°. After cooling, having tested for completeness of precipitation, the liquid is filtered, the precipitate is washed by decantation, diluted molybdenum liquid (1:3) or a solution of nitrogen-ammonium salt (150 g. NH 4 NO 3, 10 k.s. HNO 3 in 1 liter of water) until the reaction to calcium disappears (ammonium oxalate test). The precipitate is dissolved in warm dilute ammonia (1:3), filtered, the filter is washed with ammonia, and strong hydrochloric acid is added to the filtrate so much that the precipitate formed at the first moment dissolves again. To the liquid, with stirring, without touching the walls, add the magnesia mixture (0.1 g of phosphoric acid 10 kb. cm), 1/3 of the total volume of strong ammonia and leave to stand in a cool place for 2 hours. The resulting phosphorus-ammonia-magnesium salt is filtered off, washed with weak ammonia (1:3), dried, the filter is burned, moistened with nitric acid. (2-3 drops) and ignite everything. There is also a volumetric method for determining phosphoric acid, but it is only suitable when superphosphate contains only small amounts of iron and aluminum compounds (no more than 1%). To 200 kb. cm of the test solution, add 50 kb cm of acetic ammonia liquid (100 gr. NH 4 C 2 H 3 O 2 + 100 gr. C 2 H 4 O 2 per liter); if a precipitate of iron or aluminum phosphate has formed, the liquid is filtered off and a part is taken for further determinations; the precipitate is washed with hot water, calcined, weighed and 1/2 of the weight is taken for the share of R 2 O 5 . Take 50 kb. cm of the filtrate (contains 40 kb. cm of the liquid originally taken for the study) and pour in a titrated solution of uranium nitrate; the liquid is heated to a boil and, taking a drop of it, they try it from time to time on a white porcelain plate, mixing with a drop of a freshly prepared solution of yellow salt (0.25 gr. salt in 20 kb. see water). The end of the titration is determined by the formation of a brown ring in the sample. After each addition of the uranium solution, the liquid is heated to a boil. The titration is usually repeated several times in order to accurately determine the end point of the reaction. To prepare a titrated solution of uranium nitrate, dissolve 100 g. uranium nitrate in 2820 kb. cm of water and to remove the last traces of free nitric acid, 10 gr. ammonium acetate. The solution is left to stand for several days and then filtered from turbidity. The titer is determined by a solution of phosphoric acid of a known content. When determining phosphoric acid in an extract double superphosphate take 25 kb. cm liquid, dilute 50-75 kb. cm of water, add 10 kb here. cm strong nitric acid (sp. w. 1.4) and heated for 1 hour in a sand bath (to convert pyrophosphoric salts into orthophosphoric ones); the liquid is then neutralized with ammonia and acidified with nitric acid. In the future, proceed as with ordinary superphosphate.

Phosphoric acid soluble in lemon ammonia salt(citratlösliche), is usually found in superphosphates in small quantities. Many studies have been done to determine it, but all the proposed methods are not very accurate. When superphosphate is treated with a solution of lemon-ammonia salt, water-soluble phosphoric acid also goes into solution; therefore, when calculating the content of the latter, it must be determined in advance. The greater or lesser dissolution of phosphoric acid in the presence of citric ammonium salt depends on many circumstances: the relationship between the weight of the substance taken and the amount of citric acid solution, on the method of preparation of the latter, extraction time, temperature, grinding of the analyte, the presence of impurities in it (for example, gypsum ) and so on. In the analysis of superphosphates, the Petermann method is usually used; when using various other methods, results are obtained that are not comparable with each other. According to Peterman, they take a sample of superphosphate 5 g, grind it in a cup with 100 kb. cm lemon-ammonia liquid, washed into a ¼-liter flask and heated at 40 ° for an hour; the liquid is then topped up with water to the line, filtered and the phosphoric acid that has passed into the solution is determined. one of the methods described above. To prepare lemon-ammonia liquid, dissolve 400 g in water. citric acid, neutralize it with ammonia, dilute it to almost 2 liters and then, adding water, try to get a solution of beats. weight 1.09; then, for each liter of the resulting solution, 50 kb are added. see 10% ammonia. Subsequently, Peterman significantly complicated his method, without achieving, however, greater accuracy of the results.

To determine the total content of phosphoric acid 10 gr. finely ground superphosphate is boiled in a ½-liter flask for 1/2 hour with 50 kb. cm of aqua regia (3 parts hydrochloric acid, beats 1.12 and 1 part nitric acid, beats 1.25); after cooling, the liquid is diluted with water to the line, filtered, and 50 kb. cm filtrate is determined by phosphoric acid in the above way. Instead of aqua regia, 20 kb is also taken for dissolution. see nitric acid. beats in. 1.42 and 50 kb. see sulfuric acid. beats in. 1.82.

Phosphates. 1) Phosphates of mineral origin (phosphorites, apatites, etc.). To determine the moisture content of a sample of 10 gr. dried at 105-110° to constant weight. The total content of phosphoric sour determined as in the analysis of superphosphate; during the decomposition of phosphate with aqua regia, with accurate analyzes, it is necessary to transfer the released silicic acid to an insoluble state, which is not necessary when using a mixture of nitric and sulfuric acids. Determination of oxides gland and aluminum is of great importance in the analysis of phosphates, especially those intended for processing into superphosphate; in Germany, at agricultural stations, the Glaser method is in great use, indicating the content of iron oxide and aluminum oxide together. A sample of phosphate in 5 gr. dissolves in a mixture of 25 kb. cm nitric acid beats. in. 1.2 and 12.5 kb. see hydrochloric acid. beats in. 1.12 and diluted with water up to 500 kb. cm The liquid is filtered and 100 kb are taken. cm, pour into a ¼-liter flask and add 25 kb here. see sulfuric acid. beats in. 1.84. The solution is left to stand for 5 minutes. and then, while shaking, add another 100 kb. see 95% alcohol. When the liquid has cooled, alcohol is added to the line, shaken again, and since this reduces the volume, pouring alcohol to the line and shaking is repeated several times. After standing for 1/2 hour, the liquid is filtered, 100 kb are taken from it. cm and heated in a glass to remove alcohol; then add 50 kb. cm of water, bring to a boil and carefully average with ammonia to a weak alkaline reaction; in this case, phosphate salts of iron and aluminum are released; excess ammonia is removed by boiling. After cooling, the precipitate is filtered off, calcined, and 1/2 of the weight is taken as iron and aluminum oxides. Sometimes it is necessary to know the content of aluminum and iron separately. Then, according to Grueber, dissolve 10 gr. phosphate in 100 kb. cm of water, to which 20 kb is added. see strong hydrochloric acid; evaporated to dryness to isolate silica, the dry residue is treated with very weak hydrochloric acid. and everything, together with the insoluble substance, is transferred to a ½-liter flask, diluted with water to the line, shaken and filtered through a plate filter. Separate portions are taken from the resulting filtrate to determine alumina. Pour in 50 kb. cm of the filtrate (= 1 gr. sample) in a liter flask with a capacity of 200 kb. cm, neutralize with 20% sodium hydroxide, add an excess of 30 kb. cm, heated to a boil and, with shaking, give 10 minutes. stand in a warm place; after cooling, the flask is topped up to the line, shaken and filtered through a pleated filter. 50 kb. cm of the resulting filtrate (= 0.5 sample) is averaged with hydrochloric acid, ammonia is added to it in a slight excess and heated to a boil. The released phosphorus-aluminum salt is washed, dried and calcined; the weight of the AlPO 4 residue obtained, multiplied by 41.8, gives directly the percentage of alumina Al 2 O 3 . For the determination of iron oxide 100 kb. cm of the aforementioned phosphate solution is reduced with zinc and titrated under normal conditions with a chameleon - see Oxydimetry. To determine limestones, etc., in phosphates, they are decomposed with phosphoric acid and the weight of the released carbon dioxide is determined, absorbing it in a potassium apparatus. 2) Bone charcoal, bone ash, etc. Humidity, total phosphoric acids and carbonic acids are defined as in phosphates; nitrogen is according to Kjeldahl; in addition, the amount of substances insoluble in aqua regia is determined, for which a sample of 5 g is taken, dissolved in 20 kb. cm of aqua regia, boiled for 1/2 hour and the precipitate, after dilution with water, is filtered off, washed, etc. Free lime is also often determined, turning it into carbonic salt and determining the increase in carbon dioxide content, which is preliminarily determined. For this purpose, the sample is moistened several times with a strong solution of ammoniacal salt and heated to remove excess ammoniacal salt. 3) Guanophosphates. Determine the humidity, the total content of phosphoric acid, nitrogen, carbon dioxide in the same way as for other phosphates; then more ash is determined by calcining a sample of 5 g. in the crucible. The ash is boiled with 20 kb. cm hydrochloric or nitric acid, then washed, etc. to determine the content of sand in it. The so-called "precipitated phosphate".

Thomas slag flour. To determine phosphoric acid, a known portion of flour is sifted through a sieve with holes of 2 mm, and the lumps are slightly crushed by hand. The sample for phosphoric acid is taken from the portion that has passed through the sieve, and the calculation is carried out, taking into account the residue that has not been sieved; this is done on the basis that only finely divided slags are most quickly utilized in the soil. The total content of phosphoric sour found by decomposing Thomas flour with sulfuric acid; nitric acid and aqua regia are not suitable for the reason that they convert phosphorus, which is present in slags in the form of F. iron, into phosphoric acid; hydrochloric acid also turns out to be inconvenient, because it transfers various substances into solution, which are then released during the precipitation of phosphoric acid. magnesium mixture. Hanging in 10 gr. in a ½-liter flask is wetted with water, poured over 5 kb. see dilute sulfuric acid. (1:1), shaken so that it does not cake on the bottom; then pour 50 kb here. see strong sulfuric acid. and heated on a grid ¼ - ½ hour with shaking until white smoke begins to appear and the mass becomes mobile. Then water is carefully poured, shaken, cooled, topped up to the line and filtered through a double ply filter. With a long standing filtrate - gypsum may stand out from it; but this does not harm accuracy. Then proceed as described above. The dignity and price of Thomas slag flour is determined mainly by the content phosphoric sour, soluble in lemon sour According to the Wagner method, a sample of 5 gr. placed in a 1/2-liter flask containing 5 kb. cm of alcohol, and poured here at 17.5 ° to the line 2% solution of citric acid. The flask is closed with a rubber stopper and shaken for 30 minutes. using a rotating mechanical motor (30-40 rpm). The liquid is filtered, and phosphoric acid. determined in the usual way. To obtain a 2% solution of citric acid. prepare a solution containing 100 gr. acids in 1 liter; here add 0.05 gr. salicylic acid. to save. 1 volume of this solution with 4 volumes of water gives a 2% solution. Wagner proposed his method of precipitation of phosphoric acid. molybdenum liquid, as well as your recipe for making molybdenum liquid, etc .; in disputed cases, guided by his instructions. The total lime content in Thomas slag flour is found by dissolving 5 g. it in hydrochloric acid; the solution is diluted to 500 kb. cm, filter, take 50 kb. cm and lime is precipitated in them with ammonium oxalate; further determination is made as CaO, or as CaSO 4 , or finally by chameleon titration. For determining free lime sample in 2 gr. processed by shaking in a flask with a capacity of 300 kb. cm 200 kb. cm 10% sugar solution, topped up to the line, filtered, and in a certain portion calcium is precipitated by ammonium oxalate, etc. To determine silica and sand- heated in a water bath 5 gr. thomas flour with 20-25 kb. cm of strong hydrochloric acid, evaporated to dryness, dried at 120 ° - 130 ° to make the silicic acid in an insoluble state, then washed with weak hydrochloric acid, water, calcined and weighed. If you want to determine, in addition, separately sand, then the residue after weighing is boiled for some time with soda with a small addition of caustic soda, washed and the residue is ignited again. In thomas slag flour, sometimes the degree of grinding is determined by sifting it through a sieve with certain holes; after the definitions were made with citric acid, this turned out to be redundant. Specific gravity Thomas slag flour (3-3.3) can partly serve to characterize it, since it decreases when falsified with the addition of phosphates and other impurities. It is easier to determine the specific gravity by placing a certain sample, for example. 20 gr., in a wide-mouthed pycnometer in 50 kb. cm and, topping up to the line with alcohol from the buret while shaking and tapping the pycnometer to remove air bubbles. Sometimes liquids of known specific gravity are used for this purpose, for example. bromoform, a solution of a double salt of potassium iodide and mercury iodide, etc.; when testing, they look at whether the tested thomas slag meal sinks in a given liquid or does not sink. The water content is determined by drying 5 gr. substances at 100 ° for 3 hours and calcining for 15 minutes. Pure thomas slag flour contains only traces of moisture; its content is much more than 0.5% indicates the presence of impurities in it. The increase in phosphorites up to 10% is opened by testing the flour for fluorine content. Hinge 10-15 gr. decomposes in a tall glass of 15 kb. see strong sulfuric acid; the glass is covered with a watch glass with a drop of water on the underside; in the presence of phosphorites, glass is corroded by the released hydrogen fluoride.

Bone meal. Humidity is determined by drying 5 gr. at 105-110° to constant weight. Phosphoric acid is defined as for superphosphates; nitrogen - according to Kjeldahl (a sample of 1 gr.). Ash determined by firing 5 gr. substances in a platinum crucible and weighed. The residue is well wetted with ammonium carbonate, dried at 160-180°, and weighed again; get what they call residue after calcination. It is boiled in a glass for 1/2 hour with 20 kb. see hydrochloric acid and a little water, washed and calcined; receive sand; it should be no more than 9%; a larger number indicates an increase in bone meal impurities. The content of organic substances is found by difference (sample - water - residue after calcination). The addition to flour of phosphorites is recognized by the erosion of glass, as for Thomas's slag flour; the addition of gypsum is recognized by the reaction to sulfuric acid; sawdust is opened with a microscope or by the fact that they stain strong sulfuric acid. in black. Presence in bone meal skin and horns is defined as follows. 10 gr. flour is shaken in a glass cylinder with a capacity of 120 kb. cm from 100 kb. see chloroform; at the top of the liquid, particles of horn, skin, etc. float up; they are laid out with a spoon on the filter, the liquid is shaken again and the floating impurities are separated, and this is repeated several times. The filter is washed with ether, dried at 90-100° and weighed; nitrogen is determined by Kjeldahl, carbon dioxide is determined by the usual methods. To determine whether bone meal is made from defatted or non-defatted bones, determine in it fat, for what a hinge plate in 10 gr. dry well at 110° and mixed with sand, extracted with ether. Finally, for bone meal, determine grinding degree, sifting 100 gr. through sieves with specific holes. According to Shtoman, 3 sieves are used: 1 has per 1 sq. see 1089, 2 - 484 and 3 - 256 holes; what's left at 3 is designated bonemeal #4. superphosphate processed bone meal humidity is determined by drying at 100°, soluble in water, phosphoric acid, as in superphosphates, also general content phosphoric acid, and in the so-called. semi-processed bone meal is also determined by phosphoric acid, soluble in ammonium citrate.

Superphosphate-gypsum. In addition to moisture (at 110 °), water-soluble phosphoric acid and all phosphoric acid, is determined free phosphoric acid, sulfuric acid and sand. For determining free phosphoric acid sample in 5 gr. dried and shaken for 1/2 hour with 250 kb. see absolute alcohol; the liquid is then filtered, 50 kb are taken from it. cm (= 1 gr. sample), evaporated in an Erlenmeyer flask to remove alcohol, diluted with water (50 kb. cm) and precipitated phosphoric acid in the usual way.

Guano, raw Peruvian guano. When guano is dried, ammonia is also released along with water, so the determination of moisture is carried out simultaneously with the determination of ammonia, and moisture is found by the difference between the weight loss during drying and the ammonia content. Weighed in 2 gr. put in a porcelain boat in the middle of a glass tube placed in an oven. One end of this tube is connected to a calcium chloride tube, and the other end is connected to a Bill and Warrentrup device containing 100 kb. see titrated sulfuric acid. At a temperature of 110 °, air is sucked through the tube, and then, by weighing a porcelain boat, the loss in weight of the sample is determined and by titration - the amount of released ammonia. Phosphoric acid is found in Peruvian guano as water-soluble (determined as in superphosphate), soluble in ammonium citrate (Petermann's method is used to determine) and, finally, insoluble acid. Nitrogen in guano is in the form of nitrogenous organic compounds, in the form of ammonia and its salts, and in the form of nitrate salts. To determine ammonia, take 50 kb. cm (= 1 gr. sample) of an aqueous solution of guano prepared for the determination of soluble phosphoric acid., 150 kb are added here. cm of water, 3 gr. burnt magnesia and distilled off 100 kb. cm in titrated sulfuric acid. For the determination of nitric acid. take 50 kb. cm of the same aqueous solution of guano in the Kjeldal apparatus, add 120 kb here. cm of water, 5 gr. iron filings, 5 gr. zinc filings, 80 kb. cm of caustic potash in 32 ° B. and distilled off in the usual way in 20 kb. see titrated sulfuric acid; receive nitrogen nitric acid. in the form of ammonia together with the nitrogen of ammonium salts, which is determined earlier. The total nitrogen content is determined by the Jodlbauer or Forster method (see Nitrometry); nitrogen in organic compounds is found, knowing its total content, ammonia and nitrate nitrogen. To determine potassium, weigh 10 g. fired, dissolved in weak hydrochloric acid, diluted to 500 kb. cm, filter and take 100 kb. see The definition is rather troublesome, since it is necessary to remove sulfuric acid (precipitation with barium chloride), excess barium chloride (carbon am.) and phosphoric acid. Potassium is precipitated as chloroplatinate, which is separated from other chloroplatinates by washing with 80% alcohol. 100 kb. ml of the above filtrate is poured into a ½-liter flask, 5-10 kb are added. see hydrochloric acid. and 100 kb. cm of water, heated to a boil, precipitated with barium chloride and, adding ferric chloride and a little ammonia, precipitated with ammonium carbonate. Liquids are allowed to cool, diluted with water to the limit and filtered through a pleated filter. 125 kb. ml of this filtrate (= 0.5 sample) is evaporated to dryness in a platinum dish, lightly ignited to remove ammonia salts, the residue is taken up in water, filtered into a porcelain dish and evaporated to dryness. Add 2-3 kb here. cm of water and a solution of chlorine platinum (1:20; it is taken 3 1/2 kb. cm for each 1 g of the former dry residue after removal of ammonia salts); the liquid is evaporated in the absence of ammonia to a syrup state, the precipitate is cooled, triturated with a small amount of 80% alcohol, 60-50 kb are added. see alcohol and stir. After 2-3 hours. standing is filtered through a weighed filter, washed with 80% alcohol, dried for 2-3 hours at 110 ° - 120 °. Multiplying the weight of the resulting chloroplatinate by 0.1927 gives the weight of K 2 O. There are several other ways to determine potassium. Peruvian guano is often sold as an artificial mixture of superphosphates, Chilean nitrate, sulfuric ammonium salt, and so on. In the study of impurities in guano, the determination of oxalic acid (up to 18%), as well as uric acid, is of great importance. To determine oxalic acid, boil 5 g. guano in a ½-liter flask with 20 gr. soda and 20 kb. cm of water, cool, top up to the line and filter. 50 or 100 kb. cm of the filtrate is acidified with acetic acid and precipitated by boiling with calcium acetate, then proceed as usual. For the qualitative determination of uric acid. 1-2 gr. guano is evaporated carefully with weak nitric acid. dry; in the presence of uric acid. a yellow or yellowish-red precipitate remains, which turns purple from a drop of ammonia. For the quantitative determination of uric acid. apply the method of Stutzer and Karlov (A. Stutzer, A. Karlowa). AT processed sulfuric acid guano most often determine the content of soluble phosphoric acid and the total nitrogen content. Flour from meat, fish, horns, leather, powders, etc. Humidity is determined at 110 °, the total content of phosphoric acid. and ash, as with superphosphates. For the analysis of F. fertilizers, see Lunge, "Chemisch-Technische Untersuchungsmethoden".

Ca3(PO4)2 + 4C = Ca3P2 + 4CO

They are hydrolyzed by water according to the scheme: E3P2 + 6H2O = 2PH3 + 3E(OH)2. With acids, alkaline earth metal phosphides give the corresponding salt and phosphine. This is the basis for their use for the production of phosphine in the laboratory.

Complex ammonia compounds of the composition E(NH3)6 are solid substances with a metallic luster and high electrical conductivity. They are obtained by the action of liquid ammonia on E. They ignite spontaneously in air. Without air access, they decompose into the corresponding amides: E (NH3) 6 \u003d E (NH2) 2 + 4NH3 + H2. When heated, they vigorously decompose according to the same pattern.

Alkaline earth metal carbides, which are obtained by calcining E with coal, are decomposed by water with the release of acetylene: ES2 + 2H2O \u003d E (OH) 2 + C2H2. The reaction with BaC2 is so violent that it ignites on contact with water. The heats of formation of ES2 from elements for Ca and Ba are 14 and 12 kcal/mol. When heated with nitrogen, ES2 gives CaCN2, Ba(CN)2, SrCN2. Known silicides (ESi and ESi2). They can be obtained by heating directly from the elements. They hydrolyze with water and react with acids to give H2Si2O5, SiH4, the corresponding E compound, and hydrogen. Known borides EV6 obtained from the elements when heated.

Calcium oxides and its analogs are white refractory (TboilCaO = 2850оС) substances that absorb water vigorously. This is the basis for the use of BaO to obtain absolute alcohol. They react violently with water, releasing a lot of heat (except for SrO, the dissolution of which is endothermic). EO dissolve in acids and ammonium chloride: EO + 2NH4Cl = SrCl2 + 2NH3 + H2O. EO is obtained by calcining carbonates, nitrates, peroxides or hydroxides of the corresponding metals. The effective charges of barium and oxygen in BaO are ±0.86. SrO at 700 °C reacts with potassium cyanide:

KCN + SrO = Sr + KCNO.

Strontium oxide dissolves in methanol to form Sr(OCH3)2. During magnesium-thermal reduction of BaO, an intermediate oxide Ba2O can be obtained, which is unstable and disproportionate.

Hydroxides of alkaline earth metals are white substances soluble in water. They are strong bases. In the Ca-Sr-Ba series, the basic nature and solubility of hydroxides increase. pPR(Ca(OH)2) = 5.26, pPR(Sr(OH)2) = 3.5, pPR(Ba(OH)2) = 2.3. Ba(OH)2.8H2O, Sr(OH)2.8H2O, and Ca(OH)2.H2O are usually isolated from hydroxide solutions. EOs add water to form hydroxides. The use of CaO in construction is based on this. A close mixture of Ca(OH)2 and NaOH in a 2:1 weight ratio is called soda lime and is widely used as a CO2 scavenger. Ca(OH)2, when standing in air, absorbs CO2 according to the scheme: Ca(OH)2 + CO2 = CaCO3 + H2O. At about 400°C, Ca(OH)2 reacts with carbon monoxide: CO + Ca(OH)2 = CaCO3 + H2. Barite water reacts with CS2 at 100°C: CS2 + 2Ba(OH)2 = BaCO3 + Ba(HS)2 + H2O. Aluminum reacts with barite water: 2Al + Ba(OH)2 + 10H2O = Ba2 + 3H2. E(OH)2 are used to open carbonic anhydride.

E form white peroxides. They are significantly less stable than oxides and are strong oxidizers. Of practical importance is the most stable BaO2, which is a white, paramagnetic powder with a density of 4.96 g1cm3, and so on. 450°. BaO2 is stable at ordinary temperature (it can be stored for years), it is poorly soluble in water, alcohol and ether, it dissolves in dilute acids with the release of salt and hydrogen peroxide. Thermal decomposition of barium peroxide is accelerated by oxides, Cr2O3, Fe2O3 and CuO. Barium peroxide reacts when heated with hydrogen, sulfur, carbon, ammonia, ammonium salts, potassium ferricyanide, etc. Barium peroxide reacts with concentrated hydrochloric acid, releasing chlorine: BaO2 + 4HCl = BaCl2 + Cl2 + 2H2O. It oxidizes water to hydrogen peroxide: H2O + BaO2 = Ba(OH)2 + H2O2. This reaction is reversible and in the presence of even carbonic acid the equilibrium is shifted to the right. BaO2 is used as a starting product for the production of H2O2, and also as an oxidizing agent in pyrotechnic compositions. However, BaO2 can also act as a reducing agent: HgCl2 + BaO2 = Hg + BaCl2 + O2. BaO2 is obtained by heating BaO in air flow to 500°C according to the scheme: 2BaO + O2 = 2BaO2. As the temperature rises, the reverse process takes place. Therefore, when Ba burns, only oxide is released. SrO2 and CaO2 are less stable. A common method for obtaining EO2 is the interaction of E(OH)2 with H2O2, whereby EO2.8H2O is isolated. Thermal decomposition of EO2 starts at 380°C (Ca), 480°C (Sr), 790°C (Ba). When EO2 is heated with concentrated hydrogen peroxide, yellow unstable substances, EO4 superoxides, can be obtained.

SoliE are generally colorless. Chlorides, bromides, iodides and nitrates are highly soluble in water. Fluorides, sulfates, carbonates and phosphates are poorly soluble. The Ba2+ ion is toxic. Halides E are divided into two groups: fluorides and all the rest. Fluorides are almost insoluble in water and acids and do not form crystalline hydrates. On the contrary, chlorides, bromides, and iodides are highly soluble in water and are isolated from solutions in the form of crystalline hydrates. Some properties of EG2 are presented below:

). The formed ones are discharged into irrigated condensers and then collected in a receiver with, under a layer of which the molten one accumulates.

One of the methods used to obtain pH 3 is heating with strong water. goes, for example, according to the equation:

8P + ZVa (OH) 2 + 6H 2 O \u003d 2RN 3 + ZVa (H 2 RO 2) 3

HgCl 2 + H 3 PO 2 + H 2 O \u003d H 3 PO 3 + Hg + 2HCl

The latter is a white, similar to a crystalline mass (mp 24 °C, bp 175 °C). Its definitions lead to the double formula (P 4 O 6), which corresponds to the shown aa fig. 125 spatial structure.

P 2 O 3 + ZN 2 O \u003d 2H 3 RO 3

As can be seen from the above comparison, the richest is ortho-acid, which is usually called simply phosphoric. When it is heated, splitting occurs, and pyro- and meta-forms are sequentially formed:

2H 3 RO 4 \u003d H 2 O + H 4 P 2 O 7

H 4 P 2 O 7 \u003d H 2 O + 2HPO 3

ZR + 5HNO 3 + 2H 2 O \u003d ZH 3 RO 4 + 5NO

On an industrial scale, H 3 RO 4 is obtained based on P 2 O 5 formed during combustion (or it) on , is colorless, deliquescent at (mp. 42 ° C). It is usually sold in the form of 85% water, having the consistency of a thick syrup. Unlike other derivatives of H 3 RO 4 is not poisonous. Oxidizing properties are not typical for it at all.

NaH 2 PO 4 [primary phosphate]

Na 2 HPO 4 [secondary phosphate]

Na 3 PO 4 [tertiary phosphate]

Ca 3 (RO 4) 2 + 4 3 RO 4 \u003d ZCa (H 2 RO 4) 2

Sometimes, instead, HzRO 4 is neutralized, and so-called. (SaHPO 4 2H 2 O), which is also good. On many soils (having an acidic character) it is quite well absorbed by plants directly from finely ground

magnesium sulfate and water are formed?

B.Mg with H2SO4

G.MgO with H2SO4

3) What is the index of sodium in the sodium silicate formula? A. 1 B. 2 C. 3 D. 4 4) Salts, which acids are called carbonates? A. phosphoric B. silicic C. carbonic D. sulfurous 5) Anoxic acid is: A. sulfuric B. hydrogen sulfide C. sulfide D. nitric 6) Sulfates are salts of: A. Sulfurous acid B. Sulfuric acid C. Hydrosulfide acid 7 ) Oxygen-containing acids are formed by combining: A. metal oxide and water B. non-metal oxide and water C. non-metal and hydrogen D. non-metal and water 8) Which of the reactions produces soluble bases? A.H2+Cl2= B.Zn+HCl= C.Na+H2O= D.So3+H2O=

Draw its complete electronic graphic formula.

4. among the substances whose formulas are given below, indicate: 1) isomers, 2) pentane-2 homologues
5. By name, make up their graphic formulas: a) butene-2, b) 3-methylpentene-1, c) 3-methyl-4hexene-2
help me please!!! 2.4 .5

d) burning food. 2. Choose the formula of calcium phosphate: a) K2PO4; b) Ca3(PO4)2; c) Ca2 (PO4)3; d) Ca3P2. 3. Manganese exhibits an oxidation state of + 7 in the compound: a) MnO; b) Mn2O7; c) MnO2; d) K2MnO4. 4. Arrange the coefficients in the equation: ...Ba(OH)2 + ...H3PO4 = ...Ba3(PO4)2 + ...H2O. a) 3, 2, 2, 3; b) 2, 3, 1, 6; c) 3, 2, 1, 6; d) 3, 2, 0, 6. 5.c. 6. All tetrad substances interact with HCl: a) Zn, CuO, AgNO3, Cu(OH)2; b) Cu, Mg(NO3)2, Na2O, NaOH; c) KOH, HgO, K2SO4, Au; d) Na2O, NaOH, Na, NaCl. 7. Choose an exchange reaction: a) Na2O + H2O = 2NaOH; b) Zn + 2HCl = ZnCl2 + H2; c) NaOH + HCl = NaCl + H2O; d) CaCO3 = CaO + CO2. 8. The charge of the nucleus of a copper atom is: a) 64; b) +4; c) +29; d) +64. 9. The mass fraction of sulfur in sulfuric acid is: a) 0.543; b) 0.326; c) 0.128; d) 0.975. 10. Choose the formula of oxygen-free acid: a) HCl; b) KH; c) H3PO4; d) NaOH. 11. It is possible to distinguish a solution of H2SO4 from a solution of NaOH and from water using an indicator. In H2SO4 solution: a) litmus turns blue; b) methyl orange turns blue; c) methyl orange will turn red; d) phenolphthalein will turn crimson. 12. H3PO4 solution will interact with: a) NaCl; b) Ag; c) Ni; d) Cu. 13. Products of the interaction of phosphoric acid and calcium oxide: a) CaHPO4 + H2; b) Ca3(PO4)2 + H2; c) Ca3(PO4)2 + H2O; d) they don't interact. 14. Choose the correct reaction equation: a) НNO3 + NaOH = NaNO3 + H2O; b) H2O4 + Fe(OH)3 = FeSO4 + H2O; c) H2SiO3 + NaOH = Na2SiO3 + H2O; d) H2SO4 + Zn(OH)2 = ZnSO4 + H2O; 15. Formula of iron(III) silicate: a) Na2SiO3; b) FeSO4; c) Fe2(SiO3)3; d) FeSiO3. 16. Salt is soluble: a) Zn3(PO4)2; b) Ag2CO3; c) MgSiO3; d) Na2SiO3 17. It is a neutralization reaction: a) Zn + 2HCl = ZnCl2 + H2 b) 2KOH + H2SiO3 = K2SiO3 + 2 H2O; c) CaO + H2O = Ca(OH)2; d) 2Na + 2H2O = 2NaOH + H2. 18. Choose the reaction equation of the compound: a) 2NaOH + SO2 = Na2SO3 + H2O; b) Сu(OH)2 = СuO + H2O; c) 2NaOH + H2SO4 = Na2SO4 + 2 H2O; d) CaO + CO2 = CaCO3. 19. What is the mass fraction of salt in a solution if it contains 48 g of salt and the mass of the solution is 120 g a) 63; b) 31; c) 25; d) 40. 20. Calculate the mass (in g) of lithium reacted with 64 g of oxygen: 4Li + O2 = 2Li2O. a) 6.3; b) 28; c) 56; d) 84.