Did You know that!
the main component of the drink Coca-Cola - a phosphoric acid. This drink can be successfully used to remove rust from metal products!
Carbonic acid H2CO3 - it is a complex chemical substance is formed with dissolution of carbon dioxide in water:
CO2 + H2O → H2CO3.
It is one of the weak dibasic (2 hydrogen atoms) acids. In addition, it is unstable and under normal conditions spontaneously decomposes into carbon dioxide and water.
Chemical properties of carbonic acid
We know that acid can form various solts, so the carbonic acid forms of salt carbonate and bicarbonate acid salt. For example, the well - known washing soda (another name - soda ash) has the formula Na2CO3 - a highly caustic alkaline substance (chemical name is sodium carbonate). But its closest relative is baking soda (which we add, for example, in the dough). It has formula is NaHCO3 - sodium bicarbonate (or acidic salt of sodium and carbonic acid, in that the sodium atom replace not 2, but 1 hydrogen atom).
- reaction with metal oxides:
H2CO3 +CaO → CaCO3 + H2O (we get a chalk CaCO3 and water). The chalk - this is also a salt, the chemical name of which is calcium carbonate;
- reaction with alkalis and bases:
H2CO3 + 2KOH → K2CO3 + 2H2O ( formed potash is industrial name potassium carbonate salt and water);
- the reaction of the salt is formed with a weak acid:
H2CO3 + Na2SiO3 → H2SiO3 + Na2CO3. In this chemical reaction precipitate - silicic acid, and the resulting aqueous salt solution is called a solution of sodium carbonate;
- at elevated temperatures, the carbonic acid easily decomposes into carbon dioxide and water :
H2CO3 → CO2 + H2
Phosphorus can form two acids: phosphoric acid - H3PO4, that is called orthophosphoric acidand HPO 3 - metaphosphoric acid. Since the greatest interest and application received orthophosphoric acid, then first about it.
When we talk about phosphoric acid, we mean it - orthophosphoric acid
Thus, phosphoric acid - white crystals that melt at a temperature of 42 0 C, very well soluble in water. phosphoric acid has 3 hydrogen atoms, that is, is a three-base, it can form 3 types of salts, each of which replaced a different number of hydrogen atoms on the metal atom, for example.
Na3PO4 - sodium phosphate;
NaH2PO4 - sodium hydrogen phosphate;
Na2HPO4 - sodium dihydrophosphate
Of the presented sodium phosphoric acid salts, two salts have an alkaline medium - sodium phosphate and sodium dihydrophosphate. The salt sodium hydrogen phosphate has a slightly alkaline medium,
Phosphoric acid can be got in the laboratoryby with chemical reaction of phosphorus and nitric acid. This reaction occurs as:
3P + 5HNO3 + 2H2O → 3H3PO4 + 5NO
Another way to get phosphoric acid on an industrial scale. To do this, natural phosphates are treated with sulfuric acid at the following chemical reaction:
Ca3(PO4)2 + 3H2SO4 → 2H3PO4 + 3CaSO4
then, the resulting acid is filtered from calcium sulfate and evaporated. Thus, a purer concentrated acid is got
Phosphoric acid has all acid properties. Phosphoric acid is widely used in the manufacture of chemicals, mainly for the synthesis of organic substances; as fertilizer, drugs, protective and paint coatings of metals.
The General formula of metaphosphoric acids - HnPnO 3n , where n can vary from 3 to 8. Metaphosphoric acid, a glassy translucent substance. All these acids are poisonous.
Metaphosphates (salts of metaphosphoric acid, e.g. Na3P3O9, Na4P4O12) are used for descaling in boilers, for water softening.