Nitrous acid - a weak monobasic acid, which can exist only in dilute aqueous solutions of blue color in the form of gas.Salts of this acid called nitrite or nitrites.They are toxic and more stable than the acid itself.The chemical formula of the substance is as follows: HNO2.
Physical properties:
1. The molar mass equal to 47 g / mol.
2. The relative molecular weight of 27 amu
3. The density is 1.6.
4. The melting temperature is 42 degrees.
5. The boiling point is 158 degrees.
chemical properties of nitrous acid
1. If the solution with nitrous acid is heated, the chemical reaction occurs:
3HNO2 (nitrous acid) = HNO3 (nitric acid) + 2NO (nitric oxide is released as a gas) + H2O(water)
2. In aqueous solution dissociates and easily displaced from the salts of stronger acids:
H2SO4 (sulfuric acid) + 2NaNO2 (sodium nitrite) = Na2SO4 (sodium sulphate) + 2HNO2 (nitrous acid)
3. Considered ussubstance may exhibit both oxidising and reducing properties.When exposed to a strong oxidizing agents (for example, chlorine, hydrogen peroxide H2O2, potassium permanganate) is oxidized to nitric acid (in some cases the formation of salts of nitric acid):
reducing properties:
HNO2 (nitrous acid) + H2O2 (peroxidehydrogen) = HNO3 (nitric acid) + H2O (water)
HNO2 + Cl2 (chlorine) + H2O (water) = HNO3 (nitric acid) + 2HCl (hydrochloric acid)
5HNO2 (nitrous acid) + 2HMnO4 = 2Mn (NO3)2 (manganese nitrate, nitric acid salt) + HNO3 (nitric acid) + 3H2O (water)
Oxidizing properties:
2HNO2 (nitrous acid) + 2HI = 2NO (oxide oxygen as a gas) + I2 (iodine) + 2H2O (water)
Preparation of nitrous acid
This compound can be obtained in several ways: 1. By
dissolved nitrogen oxide (III) in water:
N2O3 (nitric oxide) + H2O (water) = 2HNO3 (nitrousacid)
2. The dissolution of nitrogen oxide (IV) in water:
2NO3 (nitric oxide) + H2O (water) = HNO3 (nitric acid) + HNO2 (nitrous acid)
Application nitrous acid:
- diazotization of primary aromaticamines;
- production of diazonium salts;
- in the synthesis of organic compounds (for example, for the production of organic dyes).
impact of nitrous acid in the body
This material is toxic, mutagenic effect has a striking, as is inherently deaminiruyuschim agent.
What
nitrite Nitrite - a different salt of nitrous acid.To the effects of temperature, they are less stable than the nitrates.Required in the production of certain dyes.They are used in medicine.
acquired a special significance for the human sodium nitrite.This substance has the formula NaNO2.It is used as a preservative in the food industry in the manufacture of products from fish and meat.It is a powder of pure white or slightly yellowish.Sodium nitrite is hygroscopic (with the exception of the purified sodium nitrite) and is highly soluble in H2O (water).In the air is able to slowly oxidize to sodium nitrite, has a strong regenerative properties.
Sodium nitrite is used in:
- chemical synthesis: for diazo-amino compounds to deactivate the excess sodium azide, to produce oxygen, sodium oxide and sodium oxide, for the absorption of carbon dioxide;
- Production of food (food additive E250) as an antioxidant and an antibacterial agent;
- Construction: as an antifreeze additive to concrete structures in the manufacture of construction products and, in the synthesis of organic compounds as atmospheric corrosion inhibitor, in the manufacture of rubbers, poppers, additive solution for explosives;the processing of metal to remove the layer of tin and phosphating;
- in pictures: as an antioxidant and a reagent;
- in biology and medicine: a vasodilator, antispasmodic, a laxative, a bronchodilator;as an antidote to poisoning animal or human cyanides.
also currently used and other salts of nitrous acid (such as potassium nitrite).
