Reactions confirming the relationship of various classes of inorganic substances (2)

Tasks C 2 (2013)

Reactions confirming the relationship of various classes of inorganic substances

Copper(II) oxide was heated in a current of carbon monoxide. The resulting substance was burned in an atmosphere of chlorine. The reaction product was dissolved in water. The resulting solution was divided into two parts. A solution of potassium iodide was added to one part, a solution of silver nitrate was added to the second. In both cases, the formation of a precipitate was observed. Write the equations for the four described reactions.

Copper nitrate was calcined, the resulting solid was dissolved in dilute sulfuric acid. The resulting salt solution was subjected to electrolysis. The substance released at the cathode was dissolved in concentrated nitric acid. The dissolution proceeded with evolution of brown gas. Write the equations for the four described reactions.

The iron was burned in an atmosphere of chlorine. The resulting material was treated with an excess of sodium hydroxide solution. A brown precipitate formed, which was filtered off and calcined. The residue after calcination was dissolved in hydroiodic acid. Write the equations for the four described reactions.

Metallic aluminum powder was mixed with solid iodine and a few drops of water were added. Sodium hydroxide solution was added to the resulting salt until a precipitate formed. The resulting precipitate was dissolved in hydrochloric acid. Upon subsequent addition of sodium carbonate solution, precipitation was again observed. Write the equations for the four described reactions.

As a result of incomplete combustion of coal, a gas was obtained, in the flow of which iron(III) oxide was heated. The resulting substance was dissolved in hot concentrated sulfuric acid. The resulting salt solution was subjected to electrolysis. Write the equations for the four described reactions.

A certain amount of zinc sulfide was divided into two parts. One of them was processed nitric acid and the other was fired in air. During the interaction of the evolved gases, a simple substance was formed. This substance was heated with concentrated nitric acid, and a brown gas was released. Write the equations for the four described reactions.

Sulfur was fused with iron. The reaction product was dissolved in water. The resulting gas was burned in an excess of oxygen. The combustion products were absorbed by an aqueous solution of iron(III) sulfate. Write the equations for the four described reactions.

Iron burned in chlorine. The resulting salt was added to a solution of sodium carbonate, and a brown precipitate fell out. This precipitate was filtered off and calcined. The resulting substance was dissolved in hydroiodic acid. Write the equations for the four described reactions.

The potassium iodide solution was treated with an excess of chlorine water, while the first formation of a precipitate was observed, and then its complete dissolution. The iodine-containing acid thus formed was isolated from the solution, dried, and gently heated. The resulting oxide reacted with carbon monoxide. Write down the equations of the described reactions.

Chromium(III) sulfide powder was dissolved in sulfuric acid. In this case, gas was released and a colored solution was formed. An excess of ammonia solution was added to the resulting solution, and the gas was passed through lead nitrate. The resulting black precipitate turned white after treatment with hydrogen peroxide. Write down the equations of the described reactions.

Aluminum powder was heated with sulfur powder, the resulting substance was treated with water. The resulting precipitate was treated with an excess of concentrated potassium hydroxide solution until it was completely dissolved. A solution of aluminum chloride was added to the resulting solution, and the formation of a white precipitate was again observed. Write down the equations of the described reactions.

Potassium nitrate was heated with powdered lead until the reaction ceased. The mixture of products was treated with water, and then the resulting solution was filtered. The filtrate was acidified with sulfuric acid and treated with potassium iodide. The released simple substance was heated with concentrated nitric acid. In the atmosphere of the resulting brown gas, red phosphorus was burned. Write down the equations of the described reactions.

Copper was dissolved in dilute nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution with the formation of a dark blue solution. The resulting solution was treated with sulfuric acid until the characteristic blue color of copper salts appeared. Write down the equations of the described reactions.

Magnesium was dissolved in dilute nitric acid, and no gas evolution was observed. The resulting solution was treated with an excess of potassium hydroxide solution while heating. The resulting gas was burned in oxygen. Write down the equations of the described reactions.

A mixture of potassium nitrite and ammonium chloride powders was dissolved in water and the solution heated gently. The released gas reacted with magnesium. The reaction product was added to an excess of hydrochloric acid solution, and no gas evolution was observed. The resulting magnesium salt in solution was treated with sodium carbonate. Write down the equations of the described reactions.

Aluminum oxide was fused with sodium hydroxide. The reaction product was added to an ammonium chloride solution. The released gas with a pungent odor is absorbed by sulfuric acid. The middle salt thus formed was calcined. Write down the equations of the described reactions.

Chlorine reacted with hot potassium hydroxide solution. When the solution was cooled, crystals of Berthollet salt precipitated. The resulting crystals were added to a hydrochloric acid solution. The resulting simple substance reacted with metallic iron. The reaction product was heated with a new sample of iron. Write down the equations of the described reactions.

Copper was dissolved in concentrated nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution. The resulting solution was treated with an excess of hydrochloric acid. Write down the equations of the described reactions.

Iron was dissolved in hot concentrated sulfuric acid. The resulting salt was treated with an excess of sodium hydroxide solution. The brown precipitate formed was filtered off and dried. The resulting substance was fused with iron. Write the equations for the four described reactions.

1) CuO + CO \u003d Cu + CO 2

2) Cu + Cl 2 \u003d CuCl 2

3) 2CuCl 2 + 2KI \u003d 2CuCl ↓ + I 2 + 2KCl

4) CuCl 2 + 2AgNO 3 \u003d 2AgCl ↓ + Cu (NO 3) 2

1) Cu (NO 3) 2 2CuO + 4NO 2 + O 2

2) CuO + 2H 2 SO 4 \u003d CuSO 4 + SO 2 + 2H 2 O

3) CuSO 4 + H 2 O \u003d Cu ↓ + H 2 SO 4 + O 2 (electronic

4) Cu + 4HNO 3 \u003d Cu (NO 3) 2 + 2NO 2 + 2H 2 O

1) 2Fe + 3Cl 2 = 2FeCl 3

2) FeCl 3 + 3NaOH \u003d Fe (OH) 3 ↓ + 3NaCl

4) Fe 2 O 3 + 6HI \u003d 2FeI 2 + I 2 + 3H 2 O

1) 2Al + 3I 2 \u003d 2AlI 3

2) AlI 3 + 3NaOH \u003d Al (OH) 3 + 3NaI

3) Al (OH) 3 + 3HCl \u003d AlCl 3 + 3H 2 O

4) 2AlCl 3 + 3Na 2 CO 3 + 3H 2 O \u003d 2Al (OH) 3 + 3CO 2 + 6NaCl

2) Fe 2 O 3 + CO \u003d Fe + CO 2

3) 2Fe + 6H 2 SO 4 \u003d Fe 2 (SO 4) 3 + 3SO 2 + 6H 2 O

4) Fe 2 (SO 4) 3 + 4H 2 O \u003d 2Fe + H 2 + 3H 2 SO 4 + O 2 (electrolysis)

1) ZnS + 2HNO 3 \u003d Zn (NO 3) 2 + H 2 S

2) 2ZnS + 3O 2 \u003d 2ZnO + 2SO 2

3) 2H 2 S + SO 2 \u003d 3S ↓ + 2H 2 O

4) S + 6HNO 3 \u003d H 2 SO 4 + 6NO 2 + 2H 2 O

2) FeS + 2H 2 O \u003d Fe (OH) 2 + H 2 S

3) 2H 2 S + 3O 2 2SO 2 + 2H 2 O

4) Fe 2 (SO 4) 3 + SO 2 + 2H 2 O \u003d 2FeSO 4 + 2H 2 SO 4

1) 2Fe + 3Cl 2 = 2FeCl 3

2) 2FeCl 3 + 3Na 2 CO 3 \u003d 2Fe (OH) 3 + 6NaCl + 3CO 2

3) 2Fe(OH) 3 Fe 2 O 3 + 3H 2 O

4) Fe 2 O 3 + 6HI = 2FeI 2 + I 2 + 3H 2 O

1) 2KI + Cl 2 \u003d 2KCl + I 2

2) I 2 + 5Cl 2 + 6H 2 O \u003d 10HCl + 2HIO 3

3)2HIO 3 I 2 O 5 + H 2 O

4) I 2 O 5 + 5CO \u003d I 2 + 5CO 2

1) Cr 2 S 3 + 3H 2 SO 4 \u003d Cr 2 (SO 4) 3 + 3H 2 S

2) Cr 2 (SO 4) 4 + 6NH 3 + 6H 2 O \u003d 2Cr (OH) 3 ↓ + 3 (NH 4) 2 SO 4

3) H 2 S + Pb (NO 3) 2 \u003d PbS ↓ + 2HNO 3

4) PbS + 4H 2 O 2 \u003d PbSO 4 + 4H 2 O

1) 2Al + 3S Al 2 S 3

2) Al 2 S 3 + 6H 2 O \u003d 2Al (OH) 3 ↓ + 3H 2 S

3)Al(OH) 3 +KOH=K

4) 3K + AlCl 3 \u003d 3KCl + Al (OH) 3 ↓

1) KNO 3 + Pb KNO 2 + PbO

2) 2KNO 2 + 2H 2 SO 4 + 2KI \u003d 2K 2 SO 4 + 2NO + I 2 + 2H 2 O

3) I 2 + 10HNO 3 2HIO 3 + 10NO 2 + 4H 2 O

4) 10NO 2 + P \u003d 2P 2 O 5 + 10NO

1) 3Cu + 8HNO 3 \u003d 3Cu (NO 3) 2 + 2NO + 4H 2 O

4) (OH) 2 + 3H 2 SO 4 \u003d CuSO 4 + 2 (NH 4) 2 SO 4 + 2H 2 O

1) 4Mg + 10HNO 3 \u003d 4Mg (NO 3) 2 + NH 4 NO 3 + 3H 2 O

2) Mg (NO 3) 2 + 2KOH \u003d Mg (OH) 2 ↓ + 2KNO 3

3) NH 4 NO 3 + KOHKNO 3 + NH 3 + H 2 O

4) 4NH 3 + 3O 2 \u003d 2N 2 + 6H 2 O

1) KNO 2 + NH 4 Cl KCl + N 2 + 2H 2 O

2) 3Mg + N 2 \u003d Mg 3 N 2

3) Mg 3 N 2 + 8HCl \u003d 3MgCl 2 + 2NH 4 Cl

4) 2MgCl 2 + 2Na 2 CO 3 + H 2 O \u003d (MgOH) 2 CO 3 ↓ + CO 2 + 4NaCl

1) Al 2 O 3 + 2NaOH 2NaAlO 2 + H 2 O

2) NaAlO 2 + NH 4 Cl + H 2 O \u003d NaCl + Al (OH) 3 ↓ + NH 3

3) 2NH 3 + H 2 SO 4 \u003d (NH 4) 2 SO 4

4) (NH 4) 2 SO 4 NH 3 + NH 4 HSO 4

1) 3Cl 2 + 6KOH6KCl + KClO 3 + 3H 2 O

2) 6HCl + KClO 3 \u003d KCl + 3Cl 2 + 3H 2 O

3) 2Fe + 3Cl 2 \u003d 2FeCl 3

4) 2FeCl 3 + Fe3FeCl 2

1) 3Cu + 4HNO 3 \u003d 3Cu (NO 3) 2 + 2NO 2 + 4H 2 O

2) Cu (NO 3) 2 + 2NH 3 H 2 O \u003d Cu (OH) 2 + 2NH 4 NO 3

3) Cu (OH) 2 + 4NH 3 H 2 O \u003d (OH) 2 + 4H 2 O

4) (OH) 2 + 6HCl \u003d CuCl 2 + 4NH 4 Cl + 2H 2 O

19 Document

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Tasks C-2
1. Powder of chromium (III) sulfide was dissolved in sulfuric acid. In this case, gas was released and a colored solution was formed. An excess of ammonia solution was added to the resulting solution, and the gas was passed through a solution of lead nitrate. The resulting black precipitate turned white after treatment with hydrogen peroxide. Write down the equations of the described reactions.
A mixture of potassium nitrite and ammonium chloride powders was dissolved in water and the solution heated gently. The released gas reacted with magnesium. The reaction product was added to an excess of hydrochloric acid solution, and no gas evolution was observed. The resulting magnesium salt in solution was treated with sodium carbonate. Write down the equations of the described reactions.
Copper was dissolved in dilute nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution with the formation of a dark blue solution. The resulting solution was treated with sulfuric acid until the characteristic blue color of copper salts appeared. Write down the equations of the described reactions.
Aluminum powder was heated with sulfur powder, the resulting substance was treated with water. The resulting precipitate was treated with an excess of concentrated potassium hydroxide solution until it was completely dissolved. A solution of aluminum chloride was added to the resulting solution, and the formation of a white precipitate was again observed. Write down the equations of the described reactions.
Potassium nitrate is mixed with powdered lead until the reaction stops. The product mixture was worked off with water, and then the resulting solution was filtered. The filtrate was acidified with sulfuric acid and treated with potassium iodide. The released simple substance was heated with concentrated nitric acid: In the atmosphere of the resulting brown gas, red phosphorus was burned. Write down the equations of the described reactions.
Copper was dissolved in concentrated nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution. The resulting solution was treated with an excess of hydrochloric acid. Write down the equations of the described reactions.
A solution of potassium iodide was treated with an excess of chlorine water, while observing first the formation of a precipitate, and then its complete dissolution. The resulting iodine-containing acid was isolated from the solution, dried, and gently heated. The resulting oxide reacted with carbon monoxide. Write down the equations of the described reactions.
Chlorine reacted with hot potassium hydroxide solution. When the solution was cooled, the crystals of Bertolet's salt were evaporated. The resulting crystals were added to a hydrochloric acid solution. The resulting simple substance reacted with metallic iron. The reaction product was heated with a new sample of iron. Write down the equations of the described reactions.
Aluminum oxide was fused with sodium hydroxide. The reaction products were added to the ammonium chloride solution. The released gas with a pungent odor is absorbed by sulfuric acid. The middle salt thus formed was calcined. Write down the equations of the described reactions.
Magnesium was dissolved in dilute nitric acid, and no gas evolution was observed. The resulting solution was treated with an excess of potassium hydroxide solution while heating. The resulting gas was burned in oxygen. Write down the equations of the described reactions.

EXAMPLES OF TASKS FOR INDEPENDENT SOLUTION
Sodium was burned in an excess of oxygen, the resulting crystalline substance was placed in a glass tube and carbon dioxide was passed through it. The gas coming out of the tube was collected and burned in its atmosphere of phosphorus. The resulting substance was neutralized with an excess of sodium hydroxide solution.
Aluminum carbide treated with hydrochloric acid. The released gas was burned, the combustion products were passed through lime water until a white precipitate formed, further passing the combustion products into the resulting suspension led to the dissolution of the precipitate.
Pyrite was roasted, the resulting gas with a pungent odor was passed through hydrosulfide acid. The resulting yellowish precipitate was filtered off, dried, mixed with concentrated nitric acid, and heated. The resulting solution gives a precipitate with barium nitrate.
Copper was placed in concentrated nitric acid, the resulting salt was isolated from the solution, dried and calcined. The solid reaction product was mixed with copper shavings and calcined in an inert gas atmosphere. The resulting substance was dissolved in ammonia water.
Iron filings were dissolved in dilute sulfuric acid, the resulting solution was treated with an excess of sodium hydroxide solution. The precipitate formed was filtered and left in air until it turned brown. The brown substance was calcined to constant weight.
The zinc sulfide was calcined. The resulting solid reacted completely with the potassium hydroxide solution. Carbon dioxide was passed through the resulting solution until a precipitate formed. The precipitate was dissolved in hydrochloric acid.
The gas released during the interaction of zinc with hydrochloric acid was mixed with chlorine and exploded. The resulting gaseous product was dissolved in water and treated with manganese dioxide. The resulting gas was passed through a hot solution of potassium hydroxide.
Calcium phosphide was treated with hydrochloric acid. The released gas was burned in a closed vessel, the combustion product was completely neutralized with a solution of potassium hydroxide. A solution of silver nitrate was added to the resulting solution.
Ammonium dichromate decomposed on heating. The solid decomposition product was dissolved in sulfuric acid. Sodium hydroxide solution was added to the resulting solution until a precipitate formed. Upon further addition of sodium hydroxide solution to the precipitate, it dissolved.
10. Calcium orthophosphate was calcined with coal and river sand. The resulting white glowing in the dark substance was burned in an atmosphere of chlorine. The product of this reaction was dissolved in an excess of potassium hydroxide. A solution of barium hydroxide was added to the resulting mixture.
Aluminum powder was mixed with sulfur and heated. The resulting substance was placed in water. The resulting precipitate was divided into two parts. Hydrochloric acid was added to one part, and sodium hydroxide solution was added to the other until the precipitate was completely dissolved.
Silicon was placed in a solution of potassium hydroxide, after the completion of the reaction, an excess of hydrochloric acid was added to the resulting solution. The precipitate formed was filtered off, dried and calcined. The solid calcination product reacts with hydrogen fluoride.

Tasks of the Unified State Examination of Part C2
The salt obtained by dissolving iron in hot concentrated sulfuric acid was treated with an excess of sodium hydroxide solution. The precipitate that formed was filtered off and calcined. The resulting substance was fused with iron. Write the equations of the described reactions.
The substance obtained at the cathode during the electrolysis of a sodium chloride solution with inert electrodes reacts with iodine when heated. The reaction product reacts with concentrated sulfuric acid to release gas, which is passed through a solution of potassium hydroxide. Write the equations of the described reactions.
One of the products of the interaction of ammonia with bromine - a low-reactivity gas that is part of the atmosphere - was mixed with hydrogen and passed when heated over a platinum catalyst. The gas mixture was passed through a solution of hydrochloric acid, and potassium nitrite was added to the resulting solution with slight heating. Write the equations of the described reactions.
The solution obtained by the interaction of copper with concentrated nitric acid was evaporated and the precipitate was calcined. The gaseous products of the decomposition reaction are completely absorbed by water, and hydrogen is passed over the solid residue. Write the equations for describing reactions.
A simple substance obtained by heating calcium phosphate with coke and silicon oxide was fused with calcium metal. The reaction product was treated with water, and the evolved gas was collected and passed through a hydrochloric acid solution. Write the equations for describing reactions.
A solution of ferric chloride was treated with a solution of sodium hydroxide, the precipitate that formed was separated and heated. The solid reaction product was mixed with soda ash and calcined. Sodium nitrate and sodium hydroxide were added to the remaining substance and heated at a high temperature for a long time. Write the equations for describing reactions.
Concentrated hydrochloric acid was added to lead (IV) oxide while heating. The released gas was passed through a heated solution of caustic potash. The salt of the oxygen-containing acid, which precipitated when the solution was cooled, was filtered off and dried. When the resulting salt is heated with hydrochloric acid, a poisonous gas is released, and when it is heated in the presence of manganese dioxide, a gas that is part of the atmosphere is released. Write the equations for describing reactions.
An excess of sodium hydroxide solution was added to the aluminum sulfate solution. Hydrochloric acid was added in small portions to the resulting solution, while the formation of a bulky white precipitate was observed, which dissolved with further addition of acid. A solution of sodium carbonate was added to the resulting solution. Write the equations for describing reactions.
After briefly heating an unknown orange powder, a spontaneous reaction begins, which is accompanied by a change in color to green, the release of gas and sparks. The solid residue was mixed with caustic potash and heated, the resulting substance was introduced into a dilute solution of hydrochloric acid, and a green precipitate formed, which dissolves in an excess of acid. Write the equations for describing reactions.
The nitric acid was neutralized with baking soda, the neutral solution was carefully evaporated, and the residue was calcined. The resulting substance was introduced into a solution of potassium permanganate acidified with sulfuric acid, and the solution became colorless. The nitrogen-containing reaction product was placed in a sodium hydroxide solution and zinc dust was added, and a gas with a sharp characteristic odor was released. Write the equations for describing reactions.
The substance obtained at the cathode during the electrolysis of a melt of sodium chloride was burned in oxygen. The resulting product was sequentially treated with sulfur dioxide and barium hydroxide solution. Write the equations for describing reactions.
in heated concentrated sulfuric acid a copper wire was introduced and the released gas was passed through an excess of sodium hydroxide solution. The solution was carefully evaporated, the solid residue was dissolved in water and heated with powdered sulfur. The unreacted sulfur was separated by filtration, and sulfuric acid was added to the solution, while a precipitate was observed and a gas with a pungent odor was evolved. Write the equations for describing reactions.
Quicklime was calcined with an excess of coke. The reaction product after treatment with water is used to absorb sulfur dioxide and carbon dioxide. Write the equations for describing reactions.
The substance formed during the fusion of magnesium with silicon was treated with water, as a result a precipitate formed and a colorless gas was released. The precipitate was filtered off in hydrochloric acid, and the gas was passed through a solution of potassium permanganate, and two water-insoluble binary substances were formed. Write the equations for describing reactions.
A solution of hydrochloric acid was added to a water-insoluble white salt, which occurs in nature in the form of a mineral widely used in construction and architecture. As a result, the salt dissolved and a gas was released, which, when passed through lime water, precipitated a white precipitate, which dissolved upon further passage of the gas. When the resulting solution is boiled, a precipitate forms and a gas is released. Write the equations for describing reactions.
The salt obtained by reacting zinc oxide with sulfuric acid was calcined at 800°C. The solid reaction product was treated with a concentrated alkali solution and carbon dioxide was passed through the resulting solution. Write the equations for describing reactions.
Soda ash was added to a solution of trivalent chromium sulfate. The precipitate formed was separated, transferred to a sodium hydroxide solution, bromine was added, and heated. After neutralization of the reaction products with sulfuric acid, the solution acquires an orange color, which disappears after passing through the solution. sour gas. Write the equations for describing reactions.
Phosphine was passed through a hot solution of concentrated nitric acid. The reaction products were neutralized with quicklime, the precipitate was separated, mixed with coke and silica, and calcined. The reaction product, which glows in air, was heated in a sodium hydroxide solution. Write the equations for describing reactions.
The black powder, which was formed when the red metal was burned in excess air, was dissolved in 10% sulfuric acid. Alkali was added to the resulting solution, and the resulting blue precipitate was separated and dissolved in an excess of ammonia solution. Write the equations for describing reactions.
Red phosphorus was burned in an atmosphere of chlorine. The reaction product was treated with excess water and powdered zinc was added to the solution. The released gas was passed over a heated plate of oxidized copper. Write the equations for describing reactions.
The substance obtained at the anode during the electrolysis of a sodium iodide solution on inert electrodes was introduced into a reaction with potassium. The reaction product was heated with concentrated sulfuric acid and the evolved gas was passed through a hot solution of potassium chromate. Write the equations for describing reactions.
The gas formed as a result of the reaction of hydrogen chloride with a hot solution of potassium chromium interacts with iron. The reaction product was dissolved in water, and sodium sulfide was added thereto. The lighter substance from the resulting insoluble compounds was separated and reacted with concentrated sulfuric acid by heating. Write the equations for describing reactions.
Two salts color the flame purple. One of them is colorless, and when it is lightly heated with concentrated sulfuric acid, a liquid is distilled off, in which copper dissolves; the last transformation is accompanied by the evolution of brown gas. When the second salt of the sulfuric acid solution is added to the solution, the yellow color of the solution changes to orange, and when the resulting solution is neutralized with alkali, the original color is restored. Write the equations for describing reactions.

1) Copper nitrate was calcined, the resulting solid precipitate was dissolved in sulfuric acid. Hydrogen sulfide was passed through the solution, the resulting black precipitate was calcined, and the solid residue was dissolved by heating in concentrated nitric acid.

2) Calcium phosphate was fused with coal and sand, then the resulting simple substance was burned in an excess of oxygen, the combustion product was dissolved in an excess of caustic soda. A solution of barium chloride was added to the resulting solution. The resulting precipitate was treated with an excess of phosphoric acid.

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Ca 3 (PO 4) 2 → P → P 2 O 5 → Na 3 PO 4 → Ba 3 (PO 4) 2 → BaHPO 4 or Ba (H 2 PO 4) 2 Ca 3 (PO 4) 2 + 5C + 3SiO 2 → 3CaSiO 3 + 2P + 5CO 4P + 5O 2 → 2P 2 O 5 P 2 O 5 + 6NaOH → 2Na 3 PO 4 + 3H 2 O 2Na 3 PO 4 + 3BaCl 2 → Ba 3 (PO 4) 2 + 6NaCl Ba 3 (PO 4) 2 + 4H 3 PO 4 → 3Ba(H 2 PO 4) 2

Show

Ca 3 (PO 4) 2 → P → P 2 O 5 → Na 3 PO 4 → Ba 3 (PO 4) 2 → BaHPO 4 or Ba (H 2 PO 4) 2

Ca 3 (PO 4) 2 + 5C + 3SiO 2 → 3CaSiO 3 + 2P + 5CO
4P + 5O 2 → 2P 2 O 5
P 2 O 5 + 6NaOH → 2Na 3 PO 4 + 3H 2 O
2Na 3 PO 4 + 3BaCl 2 → Ba 3 (PO 4) 2 + 6NaCl
Ba 3 (PO 4) 2 + 4H 3 PO 4 → 3Ba(H 2 PO 4) 2

3) Copper was dissolved in concentrated nitric acid, the resulting gas was mixed with oxygen and dissolved in water. Zinc oxide was dissolved in the resulting solution, then a large excess of sodium hydroxide solution was added to the solution.

4) Dry sodium chloride was treated with concentrated sulfuric acid at low heating, the resulting gas was passed into a solution of barium hydroxide. A solution of potassium sulfate was added to the resulting solution. The resulting precipitate was fused with coal. The resulting substance was treated with hydrochloric acid.

5) A sample of aluminum sulfide was treated with hydrochloric acid. In this case, gas was released and a colorless solution was formed. An ammonia solution was added to the resulting solution, and the gas was passed through a solution of lead nitrate. The precipitate thus obtained was treated with a solution of hydrogen peroxide.

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Al(OH) 3 ←AlCl 3 ←Al 2 S 3 → H 2 S → PbS → PbSO 4 Al 2 S 3 + 6HCl → 3H 2 S + 2AlCl 3 AlCl 3 + 3NH 3 + 3H 2 O → Al(OH) 3 + 3NH 4 Cl H 2 S + Pb(NO 3) 2 → PbS + 2HNO 3 PbS + 4H 2 O 2 → PbSO 4 + 4H 2 O

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Al(OH) 3 ←AlCl 3 ←Al 2 S 3 → H 2 S → PbS → PbSO 4

Al 2 S 3 + 6HCl → 3H 2 S + 2AlCl 3
AlCl 3 + 3NH 3 + 3H 2 O → Al(OH) 3 + 3NH 4 Cl
H 2 S + Pb(NO 3) 2 → PbS + 2HNO 3
PbS + 4H 2 O 2 → PbSO 4 + 4H 2 O

6) Aluminum powder was mixed with sulfur powder, the mixture was heated, the resulting substance was treated with water, while gas was released and a precipitate formed, to which an excess of potassium hydroxide solution was added until complete dissolution. This solution was evaporated and calcined. An excess of hydrochloric acid solution was added to the resulting solid.

7) A solution of potassium iodide was treated with a solution of chlorine. The resulting precipitate was treated with sodium sulfite solution. First, a solution of barium chloride was added to the resulting solution, and after separating the precipitate, a solution of silver nitrate was added.

8) A gray-green powder of chromium (III) oxide was fused with an excess of alkali, the resulting substance was dissolved in water, and a dark green solution was obtained. Hydrogen peroxide was added to the resulting alkaline solution. A yellow solution was obtained, which turns orange when sulfuric acid is added. When hydrogen sulfide is passed through the resulting acidified orange solution, it becomes cloudy and turns green again.

Show
Cr 2 O 3 → KCrO 2 → K → K 2 CrO 4 → K 2 Cr 2 O 7 → Cr 2 (SO 4) 3 Cr 2 O 3 + 2KOH → 2KCrO 2 + H 2 O 2KCrO 2 + 3H 2 O 2 + 2KOH → 2K 2 CrO 4 + 4H 2 O 2K 2 CrO 4 + H 2 SO 4 → K 2 Cr 2 O 7 + K 2 SO 4 + H 2 O K 2 Cr 2 O 7 + 3H 2 S + 4H 2 SO 4 → 3S + Cr 2 (SO 4) 3 + K 2 SO 4 + 7H 2 O

Show

Cr 2 O 3 → KCrO 2 → K → K 2 CrO 4 → K 2 Cr 2 O 7 → Cr 2 (SO 4) 3

Cr 2 O 3 + 2KOH → 2KCrO 2 + H 2 O
2KCrO 2 + 3H 2 O 2 + 2KOH → 2K 2 CrO 4 + 4H 2 O
2K 2 CrO 4 + H 2 SO 4 → K 2 Cr 2 O 7 + K 2 SO 4 + H 2 O
K 2 Cr 2 O 7 + 3H 2 S + 4H 2 SO 4 → 3S + Cr 2 (SO 4) 3 + K 2 SO 4 + 7H 2 O

9) Aluminum was dissolved in a concentrated solution of potassium hydroxide. Carbon dioxide was passed through the resulting solution until the precipitation ceased. The precipitate was filtered off and calcined. The resulting solid residue was fused with sodium carbonate.

10) Silicon was dissolved in a concentrated solution of potassium hydroxide. An excess of hydrochloric acid was added to the resulting solution. The cloudy solution was heated. The separated precipitate was filtered off and calcined with calcium carbonate. Write the equations of the described reactions.

11) Copper(II) oxide was heated in a stream of carbon monoxide. The resulting substance was burned in an atmosphere of chlorine. The reaction product was dissolved in water. The resulting solution was divided into two parts. A solution of potassium iodide was added to one part, a solution of silver nitrate was added to the second. In both cases, the formation of a precipitate was observed. Write the equations for the four described reactions.

12) Copper nitrate was calcined, the resulting solid was dissolved in dilute sulfuric acid. The resulting salt solution was subjected to electrolysis. The substance released at the cathode was dissolved in concentrated nitric acid. The dissolution proceeded with evolution of brown gas. Write the equations for the four described reactions.

13) Iron was burned in an atmosphere of chlorine. The resulting material was treated with an excess of sodium hydroxide solution. A brown precipitate formed, which was filtered off and calcined. The residue after calcination was dissolved in hydroiodic acid. Write the equations for the four described reactions.
14) Powder of metallic aluminum was mixed with solid iodine and a few drops of water were added. Sodium hydroxide solution was added to the resulting salt until a precipitate formed. The resulting precipitate was dissolved in hydrochloric acid. Upon subsequent addition of sodium carbonate solution, precipitation was again observed. Write the equations for the four described reactions.

15) As a result of incomplete combustion of coal, a gas was obtained, in the flow of which iron oxide (III) was heated. The resulting substance was dissolved in hot concentrated sulfuric acid. The resulting salt solution was subjected to electrolysis. Write the equations for the four described reactions.

16) Some amount of zinc sulfide was divided into two parts. One of them was treated with nitric acid, and the other was fired in air. During the interaction of the evolved gases, a simple substance was formed. This substance was heated with concentrated nitric acid, and a brown gas was released. Write the equations for the four described reactions.

17) Potassium chlorate was heated in the presence of a catalyst, and a colorless gas was released. By burning iron in an atmosphere of this gas, iron scale was obtained. It was dissolved in an excess of hydrochloric acid. To the solution thus obtained was added a solution containing sodium dichromate and hydrochloric acid.

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1) 2KClO 3 → 2KCl + 3O 2 2) ЗFe + 2O 2 → Fe 3 O 4 3) Fe 3 O 4 + 8HCI → FeCl 2 + 2FeCl 3 + 4H 2 O 4) 6 FeCl 2 + Na 2 Cr 2 O 7 + 14 HCI → 6 FeCl 3 + 2 CrCl 3 + 2NaCl + 7H 2 O 18) Iron burned in chlorine. The resulting salt was added to a solution of sodium carbonate, and a brown precipitate fell out. This precipitate was filtered off and calcined. The resulting substance was dissolved in hydroiodic acid. Write the equations for the four described reactions. 1) 2Fe + 3Cl 2 → 2FeCl 3 2) 2FeCl 3 + 3Na 2 CO 3 → 2Fe (OH) 3 + 6NaCl + 3CO 2 3) 2Fe(OH) 3 Fe 2 O 3 + 3H 2 O 4) Fe 2 O 3 + 6HI → 2FeI 2 + I 2 + 3H 2 O

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1) 2KClO 3 → 2KCl + 3O 2

2) ЗFe + 2O 2 → Fe 3 O 4

3) Fe 3 O 4 + 8HCI → FeCl 2 + 2FeCl 3 + 4H 2 O

4) 6 FeCl 2 + Na 2 Cr 2 O 7 + 14 HCI → 6 FeCl 3 + 2 CrCl 3 + 2NaCl + 7H 2 O

18) Iron burned in chlorine. The resulting salt was added to a solution of sodium carbonate, and a brown precipitate fell out. This precipitate was filtered off and calcined. The resulting substance was dissolved in hydroiodic acid. Write the equations for the four described reactions.

1) 2Fe + 3Cl 2 → 2FeCl 3

2) 2FeCl 3 + 3Na 2 CO 3 → 2Fe (OH) 3 + 6NaCl + 3CO 2

3) 2Fe(OH) 3 Fe 2 O 3 + 3H 2 O

4) Fe 2 O 3 + 6HI → 2FeI 2 + I 2 + 3H 2 O

19) A solution of potassium iodide was treated with an excess of chlorine water, while observing first the formation of a precipitate, and then its complete dissolution. The iodine-containing acid thus formed was isolated from the solution, dried, and gently heated. The resulting oxide reacted with carbon monoxide. Write down the equations of the described reactions.

20) Chromium(III) sulfide powder was dissolved in sulfuric acid. In this case, gas was released and a colored solution was formed. An excess of ammonia solution was added to the resulting solution, and the gas was passed through lead nitrate. The resulting black precipitate turned white after treatment with hydrogen peroxide. Write down the equations of the described reactions.

21) Aluminum powder was heated with sulfur powder, the resulting substance was treated with water. The resulting precipitate was treated with an excess of concentrated potassium hydroxide solution until it was completely dissolved. A solution of aluminum chloride was added to the resulting solution, and the formation of a white precipitate was again observed. Write down the equations of the described reactions.

22) Potassium nitrate was heated with powdered lead until the reaction ceased. The mixture of products was treated with water, and then the resulting solution was filtered. The filtrate was acidified with sulfuric acid and treated with potassium iodide. The released simple substance was heated with concentrated nitric acid. In the atmosphere of the resulting brown gas, red phosphorus was burned. Write down the equations of the described reactions.

23) Copper was dissolved in dilute nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution with the formation of a dark blue solution. The resulting solution was treated with sulfuric acid until the characteristic blue color of copper salts appeared. Write down the equations of the described reactions.

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1) 3Cu + 8HNO 3 → 3Cu (NO 3) 2 + 2NO + 4H 2 O 2) Cu (NO 3) 2 + 2NH 3 H 2 O → Cu (OH) 2 + 2NH 4 NO 3 3) Cu (OH) 2 + 4NH 3 H 2 O → (OH) 2 + 4H 2 O 4) (OH) 2 + 3H 2 SO 4 → CuSO 4 + 2 (NH 4) 2 SO 4 + 2H 2 O

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1) 3Cu + 8HNO 3 → 3Cu (NO 3) 2 + 2NO + 4H 2 O

2) Cu (NO 3) 2 + 2NH 3 H 2 O → Cu (OH) 2 + 2NH 4 NO 3

3) Cu (OH) 2 + 4NH 3 H 2 O → (OH) 2 + 4H 2 O

4) (OH) 2 + 3H 2 SO 4 → CuSO 4 + 2 (NH 4) 2 SO 4 + 2H 2 O

24) Magnesium was dissolved in dilute nitric acid, and no evolution of gas was observed. The resulting solution was treated with an excess of potassium hydroxide solution while heating. The resulting gas was burned in oxygen. Write down the equations of the described reactions.
25) A mixture of potassium nitrite and ammonium chloride powders was dissolved in water and the solution heated gently. The released gas reacted with magnesium. The reaction product was added to an excess of hydrochloric acid solution, and no gas evolution was observed. The resulting magnesium salt in solution was treated with sodium carbonate. Write down the equations of the described reactions.

26) Aluminum oxide was fused with sodium hydroxide. The reaction product was added to an ammonium chloride solution. The released gas with a pungent odor is absorbed by sulfuric acid. The middle salt thus formed was calcined. Write down the equations of the described reactions.

27) Chlorine reacted with a hot solution of potassium hydroxide. When the solution was cooled, crystals of Berthollet salt precipitated. The resulting crystals were added to a hydrochloric acid solution. The resulting simple substance reacted with metallic iron. The reaction product was heated with a new sample of iron. Write down the equations of the described reactions.
28) Copper was dissolved in concentrated nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution. The resulting solution was treated with an excess of hydrochloric acid. Write down the equations of the described reactions.

29) Iron was dissolved in hot concentrated sulfuric acid. The resulting salt was treated with an excess of sodium hydroxide solution. The brown precipitate formed was filtered off and dried. The resulting substance was fused with iron. Write the equations for the four described reactions.

30) As a result of incomplete combustion of coal, a gas was obtained, in the flow of which iron oxide (III) was heated. The resulting substance was dissolved in hot concentrated sulfuric acid. The resulting salt solution was treated with an excess of potassium sulfide solution.

31) Some amount of zinc sulfide was divided into two parts. One of them was treated with hydrochloric acid, and the other was fired in air. During the interaction of the evolved gases, a simple substance was formed. This substance was heated with concentrated nitric acid, and a brown gas was released.

32) Sulfur was fused with iron. The reaction product was treated with hydrochloric acid. The resulting gas was burned in an excess of oxygen. The combustion products were absorbed by an aqueous solution of iron(III) sulfate.