A. H2S B.SO3 C.H2SO3
2. The oxidation state of carbon in calcium carbonate is:
A. -4 B.+2 C.+4
3. A substance in which the oxidation state of phosphorus is zero:
A. P4 B.PH3 C.P2O5
4. Redox is a reaction whose equation is:
A.2Al(OH)3=Al2O3+3H2O B.H2+Cl2=2HCl C.NaOH+HNO3=NaNO3+H2O
5. An oxidizing agent in a chemical reaction, CuO+H2=Cu+H2O is:
A.H20 B.Cu2+ C.O2- D.Cu0
6. The oxidation state of chlorine decreases in the series:
A.Cl2– HCl–HClO B.NaCl–Cl2–KClO3 C.HClO4–NaClO2–BaCl2
7. The transition process, the scheme of which N-3→N+2 is:
A. Recovery
B. Oxidation
B. Not a redox process.
8. In the reaction equation S + O2 → SO2, the number of electrons donated by the oxidizing agent is:
A.2 B.4 C.6
9. Phosphorus in oxidation state 0 can be:
A.Only reductant
B. Oxidizer only
B. Oxidizing and reducing agent
10. A simple substance is a non-metal with the strongest oxidizing properties:
A. Br2
B. Cl2
B. F2
Part B.
11. Write the formulas for nitric oxide (III) and nitric oxide (V)
12. Arrange the coefficients in the reaction scheme using the electronic balance method:
Ca + O2 = CaO
Name the processes of oxidation and reduction, and indicate the oxidizing agent and reducing agent.
13. Arrange the formulas of chemical compounds: CH4, CO2, CO - in order of decreasing oxidation states of carbon atoms.
14. According to the scheme Cu + 2 + 2ē → Cu0, make up an equation for a chemical reaction and consider it from the point of view of the OVR.
15. Complete the phrase: "Restoration is ..."
determine the oxidation state of each element, arrange the coefficients using the electronic balance method: KCIO3 + S -> KCI + SO2. 3) Please determine the oxidation state of sulfur in the following compounds: H2SO4, SO2, H2S, SO2, H2SO3. 4 towards the atoms of which chemical element do common electron pairs shift in the molecules of the following compounds: H2O, HI, PCI3, H3N, H2S, CO2? please give a valid answer! 5) tell me, do the oxidation states of atoms change when water is formed from hydrogen and oxygen? 6) write the equations of electrolytic dissociation: copper nitrate, hydrochloric acid s, aluminum sulfate, barium hydroxide, zinc sulfate. 7) please write the molecular and ionic equations of reactions between solutions: lithium hydroxide and nitric acid, copper nitrate and sodium hydroxide, potassium carbonate and phosphoric acid. 8) in the interaction of solutions of which substances, one of the reaction products is water? K2CO3 and HCI: Ca(OH)2 and HNO3: NaOH and H2SO4: NaNO3 and H2SO4? Please write the reaction equations in molecular and ionic formulas. 9) which of the following salts undergo hydrolysis when dissolved in water: aluminum chloride, potassium sulfide, sodium chloride? Write equations for hydrolysis.
Under normal conditions, nitric acid is a colorless liquid (density 1.52 g/cm 3 ), boiling at 82.6 o C, and at a temperature (-41.6 o C) solidifying into a transparent crystalline mass. Gross formula - HNO 3 . Molar mass - 93 g/mol. The structure of the nitric acid molecule is shown in fig. one.
Nitric acid is miscible with water in any ratio. It is a strong electrolyte, i.e. in aqueous solution almost completely dissociates into ions. In OVR, it acts as an oxidizing agent.
Rice. 1. The structure of the nitric acid molecule, indicating the bond angles between bonds and the lengths of chemical bonds.
HNO3, oxidation states of elements in it
To determine the oxidation states of the elements that make up nitric acid, you first need to figure out for which elements this value is exactly known.
The oxidation states of hydrogen and oxygen in the composition of inorganic acids are always equal to (+1) and (-2), respectively. To find the oxidation state of nitrogen, let's take its value as "x" and determine it using the electroneutrality equation:
(+1) + x + 3×(-2) = 0;
1 + x - 6 = 0;
So the degree of oxidation of nitrogen in nitric acid is (+5):
H +1 N +5 O -2 3 .
Examples of problem solving
EXAMPLE 1
Compounds with an oxidation state of –3. Nitrogen compounds in the -3 oxidation state are represented by ammonia and metal nitrides.
Ammonia- NH 3 is a colorless gas with a characteristic pungent odor. The ammonia molecule has the geometry of a trigonal pyramid with a nitrogen atom at the top. The atomic orbitals of nitrogen are in sp 3- hybrid state. Three orbitals are involved in the formation of nitrogen-hydrogen bonds, and the fourth orbital contains an unshared electron pair, the molecule has a pyramidal shape. The repulsive action of the lone pair of electrons causes the bond angle to decrease from the expected 109.5 to 107.3°.
At a temperature of -33.4 °C, ammonia condenses to form a liquid with a very high heat of vaporization, which allows it to be used as a refrigerant in industrial refrigeration systems.
The presence of an unshared electron pair at the nitrogen atom allows it to form another covalent bond according to the donor-acceptor mechanism. Thus, in an acidic environment, the formation of the molecular ammonium cation - NH 4 + occurs. The formation of a fourth covalent bond leads to alignment of bond angles (109.5°) due to the uniform repulsion of hydrogen atoms.
Liquid ammonia is a good self-ionizing solvent:
2NH 3 NH 4 + + NH 2 -
amide anion
It dissolves alkali and alkaline earth metals, forming colored conductive solutions. In the presence of a catalyst (FeCl 3), the dissolved metal reacts with ammonia to release hydrogen and form an amide, for example:
2Na + 2NH 3 \u003d 2NaNH 2 + H 2
sodium amide
Ammonia is very soluble in water (at 20 °C, about 700 volumes of ammonia dissolve in one volume of water). In aqueous solutions, it exhibits the properties of a weak base.
NH 3 + H 2 O ® NH 3 × H 2 O NH 4 + + OH -
= 1.85 10 -5
In an oxygen atmosphere, ammonia burns with the formation of nitrogen; on a platinum catalyst, ammonia is oxidized to nitric oxide (II):
4NH 3 + 3O 2 = 2N 2 + 6H 2 O; 4NH 3 + 5O 2 \u003d 4NO + 6H 2 O
As a base, ammonia reacts with acids to form salts of the ammonium cation, for example:
NH 3 + HCl = NH 4 Cl
Ammonium salts are highly soluble in water and slightly hydrolyzed. In the crystalline state, they are thermally unstable. The composition of thermolysis products depends on the properties of the acid forming the salt:
NH 4 Cl ® NH 3 + HCl; (NH 4) 2 SO 4 ® NH 3 + (NH 4) HSO 4
(NH 4) 2 Cr 2 O 7 ® N 2 + Cr 2 O 3 + 4H 2 O
Under the action of alkalis on aqueous solutions of ammonium salts, ammonia is released during heating, which makes it possible to use this reaction as a qualitative one for ammonium salts and as a laboratory method for obtaining ammonia.
NH 4 Cl + NaOH \u003d NaCl + NH 3 + H 2 O
In industry, ammonia is obtained by direct synthesis.
N 2 + 3H 2 2NH 3
Since the reaction is highly reversible, the synthesis is carried out at elevated pressure (up to 100 MPa). To speed up the process, the process is carried out in the presence of a catalyst (spongy iron promoted by additives) and at a temperature of about 500°C.
Nitride are formed as a result of the reactions of many metals and non-metals with nitrogen. The properties of nitrides naturally change in a period. For example, for elements of the third period:
Nitrides of s-elements of groups I and II are crystalline salt-like substances that are easily decomposed by water to form ammonia.
Li 3 N + 3H 2 O \u003d 3LiOH + NH 3
Of the halogen nitrides in the free state, only Cl 3 N was isolated, the acid character manifests itself in the reaction with water:
Cl 3 N + 3H 2 O \u003d 3HClO + NH 3
The interaction of nitrides of different nature leads to the formation of mixed nitrides:
Li 3 N + AlN \u003d Li 3 AlN 2; 5Li 3 N + Ge 3 N 4 = 3Li 5 GeN 3
lithium nitridoaluminate nitridogermanate(IV) lithium
BN, AlN, Si 3 N 4, Ge 3 N 4 nitrides are solid polymeric substances with high melting points (2000-3000 ° C), they are semiconductors or dielectrics. Nitrides of d-metals - crystalline compounds of variable composition (bertolides), very hard, refractory and chemically stable, exhibit metallic properties: metallic luster, electrical conductivity.
Compounds with an oxidation state of –2. Hydrazine - N 2 H 4 - the most important inorganic nitrogen compound in the -2 oxidation state.
Hydrazine is a colorless liquid with a boiling point of 113.5 °C, fuming in air. Hydrazine vapors are extremely toxic and form explosive mixtures with air. Hydrazine is obtained by oxidizing ammonia with sodium hypochlorite:
2N -3 H 3 + NaCl +1 O \u003d N 2 -2 H 4 + NaCl -1 + H 2 O
Hydrazine is miscible with water in any ratio and behaves in solution as a weak diacid base, forming two series of salts.
N 2 H 4 + H 2 O N 2 H 5 + + OH - , K b = 9.3×10 -7;
hydrosonium cation
N 2 H 5 + + H 2 O N 2 H 6 2+ + OH - , K b = 8.5×10 -15;
dihydrosonium cation
N 2 H 4 + HCl N 2 H 5 Cl; N 2 H 5 Cl + HCl N 2 H 6 Cl 2
hydrosonium chloride dihydrosonium dichloride
Hydrazine is the strongest reducing agent:
4KMn +7 O 4 + 5N 2 -2 H 4 + 6H 2 SO 4 \u003d 5N 2 0 + 4Mn +2 SO 4 + 2K 2 SO 4 + 16H 2 O
Unsymmetrical dimethylhydrazine (heptyl) is widely used as a rocket fuel.
Compounds with an oxidation state of –1. Hydroxylamine - NH 2 OH - the main inorganic nitrogen compound in the oxidation state -1.
Hydroxylamine is obtained by reducing nitric acid with hydrogen at the time of isolation during electrolysis:
HNO 3 + 6H \u003d NH 2 OH + 2H 2 O
This is a colorless crystalline substance (mp. 33 ° C), highly soluble in water, in which it exhibits the properties of a weak base. With acids it gives hydroxylammonium salts - stable, colorless substances, soluble in water.
NH 2 OH + H 2 O + + OH - , K b = 2×10 -8
hydroxylammonium ion
The nitrogen atom in the NH 2 OH molecule exhibits an intermediate oxidation state (between -3 and +5), so hydroxylamine can act both as a reducing agent and as an oxidizing agent:
2N -1 H 2 OH + I 2 + 2KOH = N 0 2 + 2KI + 4H 2 O;
reducing agent
2N -1 H 2 OH + 4FeSO 4 + 3H 2 SO 4 = 2Fe 2 (SO 4) 3 + (N -3 H 4) 2 SO 4 + 2H 2 O
oxidizing agent
NH 2 OH easily decomposes when heated, undergoing disproportionation:
3N -1 H 2 OH \u003d N 0 2 + N -3 H 3 + 3H 2 O;
Compounds with an oxidation state of +1. Nitric oxide (I) - N 2 O (nitrous oxide, laughing gas). The structure of its molecule can be conveyed by the resonance of two valence schemes, which show that this compound can be considered as nitric oxide (I) only formally, in reality it is nitrogen (V) oxynitride - ON +5 N -3.
N 2 O is a colorless gas with a slight pleasant smell. In small concentrations it causes bouts of unbridled joy, in large doses it has a general anesthetic effect. A mixture of nitrous oxide (80%) and oxygen (20%) was used in medicine for anesthesia.
Under laboratory conditions, nitric oxide (I) can be obtained by decomposition of ammonium nitrate. N 2 O obtained by this method contains impurities of higher nitrogen oxides, which are extremely toxic!
NH 4 NO 3 ¾® N 2 O + 2H 2 O
By chemical properties nitric oxide (I) is a typical non-salt-forming oxide, it does not react with water, acids and alkalis. When heated, it decomposes to form oxygen and nitrogen. For this reason, N 2 O can act as an oxidizing agent, for example:
N 2 O + H 2 \u003d N 2 + H 2 O
Compounds with an oxidation state of +2. Nitric oxide (II) - NO - colorless gas, extremely toxic. In air, it is rapidly oxidized by oxygen to form no less toxic nitric oxide (IV). In industry, NO is produced by the oxidation of ammonia on a platinum catalyst or by passing air through an electric arc (3000-4000 °C).
4NH 3 + 5O 2 \u003d 4NO + 6H 2 O; N 2 + O 2 \u003d 2NO
A laboratory method for obtaining nitric oxide (II) is the interaction of copper with dilute nitric acid.
3Cu + 8HNO 3 (diff.) = 3Cu(NO 3) 2 + 2NO + 4H 2 O
Nitric oxide (II) is a non-salt-forming oxide, a strong reducing agent, easily reacts with oxygen and halogens.
2NO + O 2 \u003d 2NO 2; 2NO + Cl 2 = 2NOCl
nitrosyl chloride
At the same time, when interacting with strong reducing agents, NO acts as an oxidizing agent:
2NO + 2H 2 = N 2 + 2H 2 O; 10NO + 4Р = 5N 2 + 2Р 2 O 5
Compounds with an oxidation state of +3. Nitric oxide (III) - N 2 O 3 - an intensely blue liquid (t.cr. -100 ° C). Stable only in liquid and solid state at low temperatures. It appears to exist in two forms:
Nitric oxide(III) is obtained by co-condensation of NO and NO 2 vapors. Dissociates in liquids and vapors.
NO 2 + NO N 2 O 3
Typical properties acid oxide. It reacts with water, forming nitrous acid, with alkalis forms salts - nitrites.
N 2 O 3 + H 2 O \u003d 2HNO 2; N 2 O 3 + 2NaOH \u003d 2NaNO 2 + H 2 O
Nitrous acid- medium strength acid (K a = 1×10 -4). It has not been isolated in its pure form, in solutions it exists in two tautomeric forms (tautomers are isomers that are in dynamic equilibrium).
nitrite form nitro form
Salts of nitrous acid are stable. The nitrite anion exhibits a pronounced redox duality. Depending on the conditions, it can perform both the function of an oxidizing agent and the function of a reducing agent, for example:
2NaNO 2 + 2KI + 2H 2 SO 4 = I 2 + 2NO + K 2 SO 4 + Na 2 SO 4 + 2H 2 O
oxidizing agent
KMnO 4 + 5NaNO 2 + 3H 2 SO 4 = 2MnSO 4 + 5NaNO 3 + K 2 SO 4 + 3H 2 O
reducing agent
Nitrous acid and nitrites are prone to disproportionation:
3HN +3 O 2 \u003d HN +5 O 3 + 2N +2 O + H 2 O
Compounds with an oxidation state of +4. Nitric oxide (IV) - NO 2 - brown gas, with a sharp unpleasant odor. Extremely toxic! In industry, NO 2 is produced by the oxidation of NO. The laboratory method for obtaining NO 2 is the interaction of copper with concentrated nitric acid, as well as the thermal decomposition of lead nitrate.
Cu + 4HNO 3 (conc.) = Cu(NO 3) 2 + 2NO 2 + 2H 2 O;
2Pb(NO 3) 2 \u003d 2PbO + 4NO 2 + O 2
The NO 2 molecule has one unpaired electron and is a stable free radical, so nitric oxide easily dimerizes.
The dimerization process is reversible and very sensitive to temperature:
paramagnetic, diamagnetic,
brown colorless
Nitrogen dioxide is an acidic oxide that reacts with water to form a mixture of nitric and nitrous acid (mixed anhydride).
2NO 2 + H 2 O \u003d HNO 2 + HNO 3; 2NO 2 + 2NaOH \u003d NaNO 3 + NaNO 2 + H 2 O
Compounds with an oxidation state of +5. Nitric oxide (V) - N 2 O 5 - white crystalline substance. Obtained by dehydration of nitric acid or oxidation of nitric oxide (IV) with ozone:
2HNO 3 + P 2 O 5 \u003d N 2 O 5 + 2HPO 3; 2NO 2 + O 3 \u003d N 2 O 5 + O 2
In the crystalline state, N 2 O 5 has a salt-like structure - + -, in vapor (t. vozg. 33 ° C) - molecular.
N 2 O 5 - acid oxide - nitric acid anhydride:
N 2 O 5 + H 2 O \u003d 2HNO 3
Nitric acid- HNO 3 - a colorless liquid with a boiling point of 84.1 ° C, decomposes when heated and in the light.
4HNO 3 \u003d 4NO 2 + O 2 + 2H 2 O
Nitrogen dioxide impurities give concentrated nitric acid a yellow-brown color. Nitric acid is miscible with water in any ratio and is one of the strongest mineral acids; it completely dissociates in solution.
The structure of the nitric acid molecule is described by the following structural formulas:
Difficulties with writing the structural formula of HNO 3 are caused by the fact that, showing in this compound the oxidation state +5, nitrogen, as an element of the second period, can form only four covalent bonds.
Nitric acid is one of the strongest oxidizing agents. The depth of its recovery depends on many factors: concentration, temperature, reducing agent. Usually, when oxidized with nitric acid, a mixture of reduction products is formed:
HN +5 O 3 ® N +4 O 2 ® N +2 O ® N +1 2 O ® N 0 2 ® +
The predominant product of the oxidation of non-metals and inactive metals with concentrated nitric acid is nitric oxide (IV):
I 2 + 10HNO 3 (conc) = 2HIO 3 + 10NO 2 + 4H 2 O;
Pb + 4HNO 3 (conc) = Pb (NO 3) 2 + 2NO 2 + 2H 2 O
Concentrated nitric acid passivates iron and aluminum. Aluminum is passivated even with dilute nitric acid. Nitric acid of any concentration does not affect gold, platinum, tantalum, rhodium and iridium. Gold and platinum are dissolved in aqua regia - a mixture of concentrated nitric and hydrochloric acids in a ratio of 1: 3.
Au + HNO 3 + 4HCl \u003d H + NO + 2H 2 O
The strong oxidizing effect of aqua regia is due to the formation of atomic chlorine during the decomposition of nitrosyl chloride, a product of the interaction of nitric acid with hydrogen chloride.
HNO 3 + 3HCl \u003d Cl 2 + NOCl + 2H 2 O;
NOCl = NO + Cl×
An effective solvent for low-active metals is a mixture of concentrated nitric and hydrofluoric acids.
3Ta + 5HNO 3 + 21HF = 3H 2 + 5NO + 10H 2 O
Diluted nitric acid, when interacting with non-metals and low-active metals, is reduced mainly to nitric oxide (II), for example:
3P + 5HNO 3 (razb) + 2H 2 O \u003d 3H 3 PO 4 + 5NO;
3Pb + 8HNO 3 (razb) \u003d 3Pb (NO 3) 2 + 2NO + 4H 2 O
Active metals reduce dilute nitric acid to N 2 O, N 2 or NH 4 NO 3, for example,
4Zn + 10HNO 3 (razb) \u003d 4Zn (NO 3) 2 + NH 4 NO 3 + 3H 2 O
The bulk of nitric acid goes to the production of fertilizers and explosives.
Nitric acid is produced industrially by the contact or arc method, which differ in the first stage - the production of nitric oxide (II). The arc method is based on the production of NO by passing air through an electric arc. In the contact process, NO is produced by the oxidation of ammonia with oxygen over a platinum catalyst. Next, nitric oxide (II) is oxidized to nitric oxide (IV) by atmospheric oxygen. By dissolving NO 2 in water in the presence of oxygen, nitric acid is obtained with a concentration of 60-65%.
4NO 2 + O 2 + 2H 2 O \u003d 4HNO 3
If necessary, nitric acid is concentrated by distillation with concentrated sulfuric acid. In the laboratory, 100% nitric acid can be obtained by the action of concentrated sulfuric acid on crystalline sodium nitrate when heated.
NaNO 3 (cr) + H 2 SO 4 (conc) = HNO 3 + NaHSO 4
Salts of nitric acid- nitrates - highly soluble in water, thermally unstable. The decomposition of nitrates of active metals (excluding lithium), which are in the series of standard electrode potentials to the left of magnesium, leads to the formation of nitrites. For example:
2KNO 3 = 2KNO 2 + O 2
During the decomposition of lithium and magnesium nitrates, as well as metal nitrates located in the series of standard electrode potentials to the right of magnesium, up to copper, a mixture of nitric oxide (IV) and oxygen is released. For example:
2Cu(NO 3) 2 \u003d 2CuO + 4NO 2 + O 2
Nitrates of metals located at the end of the activity series decompose to free metal:
2AgNO 3 \u003d 2Ag + 2NO 2 + O 2
Sodium, potassium and ammonium nitrates are widely used for the production of gunpowder and explosives, as well as nitrogen fertilizers (saltpeter). Ammonium sulfate, ammonia water and carbamide (urea) - full carbonic acid amide are also used as fertilizers:
Hydrogen azide(dinitridonitrate) - HN 3 (HNN 2) - a colorless volatile liquid (mp -80 ° C, bp 37 ° C) with a pungent odor. The central nitrogen atom is in sp hybridization, the oxidation state is +5, the atoms adjacent to it have an oxidation state of –3. Molecule structure:
An aqueous solution of HN 3 - hydronitrous acid is close in strength to acetic acid, K a \u003d 2.6 × 10 -5. Stable in dilute solutions. It is obtained by the interaction of hydrazine and nitrous acid:
N 2 H 4 + HNO 2 \u003d HN 3 + 2H 2 O
In terms of oxidizing properties, HN 3 (HN +5 N 2) resembles nitric acid. So, if the interaction of a metal with nitric acid produces nitric oxide (II) and water, then with hydrazoic acid - nitrogen and ammonia. For example,
Cu + 3HN +5 N 2 = Cu(N 3) 2 + N 2 0 + NH 3
A mixture of HN 3 and HCl behaves like aqua regia. Salts of hydronitrous acid - azides. Only azides are relatively stable alkali metals, at temperatures > 300 °C they are destroyed without explosion. The rest disintegrate with an explosion on impact or heating. Lead azide is used in the production of detonators:
Pb(N 3) 2 = Pb + 3N 2 0
The starting product for the production of azides is NaN 3, which is formed as a result of the reaction of sodium amide and nitric oxide (I):
NaNH 2 + N 2 O \u003d NaN 3 + H 2 O
4.2 Phosphorus
Phosphorus is represented in nature by one isotope - 31 P, the clarke of phosphorus is 0.05 mol.%. It occurs in the form of phosphate minerals: Ca 3 (PO 4) 2 - phosphorite, Ca 5 (PO 4) 3 X (X \u003d F, Cl, OH) - apatites. It is part of the bones and teeth of animals and humans, as well as the composition of nucleic acids (DNA and RNA) and adenosine phosphoric acids (ATP, ADP and AMP).
Phosphorus is obtained by reduction of phosphorite with coke in the presence of silicon dioxide.
Ca 3 (PO 4) 2 + 3SiO 2 + 5C = 3CaSiO 3 + 2P + 5CO
A simple substance - phosphorus - forms several allotropic modifications, of which the main ones are white, red and black phosphorus. White phosphorus is formed during the condensation of phosphorus vapor and is a white wax-like substance (mp 44 ° C), insoluble in water, soluble in some organic solvents. White phosphorus has a molecular structure and consists of tetrahedral molecules P 4 .
Bond strength (valence P-P-P angle is only 60 °) causes a high reactivity and toxicity of white phosphorus (lethal dose of about 0.1 g). Since white phosphorus is highly soluble in fats, milk cannot be used as an antidote for poisoning. In air, white phosphorus spontaneously ignites, so it is stored in a hermetically sealed chemical container under a layer of water.
Red phosphorus has a polymer structure. It is obtained by heating white phosphorus or irradiating it with light. Unlike white phosphorus, it is slightly reactive and non-toxic. However, residual amounts of white phosphorus can make red phosphorus toxic!
Black phosphorus is obtained by heating white phosphorus under a pressure of 120 thousand atm. It has a polymer structure, has semiconductor properties, is chemically stable and non-toxic.
Chemical properties. White phosphorus is spontaneously oxidized by atmospheric oxygen at room temperature (oxidation of red and black phosphorus occurs when heated). The reaction proceeds in two stages and is accompanied by luminescence (chemiluminescence).
2P + 3O 2 \u003d 2P 2 O 3; P 2 O 3 + O 2 \u003d P 2 O 5
Phosphorus also reacts stepwise with sulfur and halogens.
2P + 3Cl 2 \u003d 2PCl 3; PCl 3 + Cl 2 = PCl 5
When interacting with active metals, phosphorus acts as an oxidizing agent, forming phosphides - phosphorus compounds in the -3 oxidation state.
3Ca + 2P = Ca 3 P 2
Oxidizing acids (nitric and concentrated sulfuric acids) oxidize phosphorus to phosphoric acid.
P + 5HNO 3 (conc) = H 3 PO 4 + 5NO 2 + H 2 O
When boiling with alkali solutions, white phosphorus disproportionates:
4P 0 + 3KOH + 3H 2 O = P -3 H 3 + 3KH 2 P +1 O 2
phosphine potassium hypophosphite
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