Nitrous acid is a weak monobasic acid, which can exist only in dilute aqueous solutions in blue and gas form. The salt of this acid is called nitrite or nitrite. They are more toxic and more resistant to acids. The chemical formula of this substance is as follows: HNO2.
1. The molar mass is 47 g/mol.
2. The relative molecular weight is 27 amu.
3. Density is 1.6.
4. The melting point is 42 degrees.
5. The boiling point is 158 degrees.
Chemical Properties of Nitrous Acid
1. If the solution is heated with nitrous acid, the following chemical reaction will occur:
3HNO2 (nitrous acids) = HNO 3 (nitric acids) + 2NO (nitrogen oxide, released as gas) + H 2 O (Water)
2. In aqueous solutions, it is isolated and easily displaced from salts by strong acids:
H 2 SO 4 (sulfuric acid) + 2 NaNO 2 (sodium nitrite) = Na 2 SO 4 (sodium sulfate) + 2HNO2 (nitrous acid)
3. We may present the substance in question as having oxidizing and reducing properties. Oxidation of nitric acid (in some cases the formation of nitric acid salts) when exposed to a strong oxidizing agent (for example, chlorine, hydrogen peroxide H2O2, potassium permanganate):
HOO 2 (nitrous acid) + H 2 O 2 (hydrogen peroxide) = HON 3 (nitric acid) + H 2 O (water)
HOO 2 + Cl 2 (chlorine) + H 2 O (water) = HNO 3 (nitric acid) ) + 2 HCl (hydrochloric acid)
5HNO2 (nitrous acid) + 2 HMNO 4 = 2 Mn (NO.3) 2 (manganese nitrate, nitric acid salt) + HNO 3 (nitric acid) + 3H 2 O (water)
2HNO2 (nitrous acid) + 2HI = 2NO (oxygen oxide, as gas) + I2 (iodine) + 2H 2 O (water)
production of nitrous acid
This substance can be obtained in several ways:
1. When Nitrogen (III) is dissolved in water:
N 2 O 3 (nitric oxide) + H 2 O (water) = 2HNO3 (nitrous acid)
2. When the oxide of nitrogen (IV) is dissolved in water:
2NO3 (nitric oxide) + H 2 O (water) = HNO 3 (Nitric Acid) + HOO 2 (Nitrous Acid)
Application of nitrous acid:
– Diazitation of aromatic primary amines;
– production of diazonium salts;
– in the synthesis of organic substances (for example, for the production of organic dyes)
The effect of nitrous acid on the body
This substance is toxic, has a bright mutagenic effect, because in essence it is a deaminating agent.
What are nitrates
Nitrites are various salts of nitrous acid. As for the effect of temperature, they are less stable than nitrates. Necessary for the production of certain dyes applied in medicine
For a person nitrite has acquired special importancesodium. This substance has the formula Nano 2. Used as a preservative in the food industry for the production of fish and meat products. It is a pure white or slightly yellowish powder. Sodium nitrite is hygroscopic (except pure sodium nitrite) and readily soluble in H2O (water). In air it can slowly oxidize to sodium nitrate, has strong reducing properties.
Sodium nitrite is used in:
– Chemical synthesis: to produce oxygen, sodium oxide and sodium nitrogen, to neutralize excess sodium azide, to produce dizomine compounds, to absorb carbon dioxide ;
– in the production of food products (food additive E250): as an antioxidant and antibacterial agent;
– in construction: in the synthesis of organic substances, as a corrosion inhibitor of atmospheric, antifreeze additive in concrete, in the manufacture of structures and construction products in the production of mortar additives for rubbers, poppers, explosives; when processing the metal during removal and phosphating of the tin layer;
– In photography: as an antioxidant and reagent;
– in biology and medicine: vasodilator, spasmolytic, laxative, bronchodilator; As an antidote for poisoning with an animal or human cyanide.