Chemical properties

1. Interaction with acidic oxides forming the salts and water:

2LiOH + SO₃ = Li₂SO₄ + H₂O;

Cа(OH)₂ + N₂O₅ = Ca(NO₃)₂ + H₂O;

2. Interaction with acids forming the salts and water:

2LiOH + H₂SO₄ = Li₂SO₄ +2H₂O;

Cа(OH)₂ + 2HNO₃ = Ca(NO₃)₂ + 2H₂O;

3. Interaction with amphoteric oxides forming the salts and water:

2KOH + ZnO = K₂ZnO₂ + H₂O;

3Ba(OH)₂ + Al₂O₃ = Ba₃(AlO₃)₂ + 3H₂O;

4. Interaction with amphoteric hydroxides forming the salts and water:

3NaOH + Cr(OH)₃ = Na₃CrO₃ + 3H₂O;

Ca(OH)₂ + Sn(OH)₂ = CaSnO₂ + 2H₂O;

5. Alkalis react with some salts:

2NH₄Cl + Sr(OH)₂ = 2NH₄OH + SrCl₂;

Fe₂(SO₄)₃ + 6LiOH = 2Fe(OH)₃ + 3Li₂SO₄.

Acids

Acids are the complex substances, consisting from Hydrogen atoms and acid radical (residue).

According to quantity of H⁺ (basicity) acids may be divided into:

One-basic (HCl, HNO₃, HClO₄, CH₃–COOH etc.);

Two-basic (H₂CO₃, H₂SO₃, H₂SO₄ etc.);

Three-basic (H₃BO₃, H₃PO₄, H₃AsO₄ etc.);

Four-basic (H₄SiO₄, H₄P₂O₇ etc.).

There are two types of acids depending on their chemical composition: Oxyacids - contain Oxygen (the most of acids - H₂CO₃, H₂SiO₃, HNO₃, H₃PO₄, H₂SO₃, H₂SO₄, HClO₄ etc.) and Oxygen-free acids (HF, HCl, HBr, HI, H₂S, H₂Se, HCN, HSCN etc.).

Oxyacids are hydrated forms of acidic oxides (anhydrides). The most of such oxides may react with water directly forming hydrates - acids. For example, Sulfuric acid is a hydrate of Sulfur (VI) oxide.

The total characteristics of the usual acids are presented in Appendix 4.

Preparation

1. Oxygen-free acids may be prepared by interaction between corresponding non-metals and free Hydrogen and following dissolution of gaseous products in water:

H₂ + Cl₂ = 2HCl;

H₂ + S = H₂S;

2. Oxygen-free acids are synthesized by action of strong acids to corresponding salts of Oxygen-free acids:

CaF₂ + H₂SO₄ = CaSO₄ + 2HF;

FeS + 2HCl = FeCl₂ + H₂S;

3. Interaction of acidic oxides (anhydrides) with water:

SO₃ + H₂O = H₂SO₄;

Cl₂O₇ + H₂O = 2HClO₄;

4. If anhydrides do not react with water directly, the corresponding acids may be prepared by action of strong acids to responding soluble salt of needed acid:

H₂SO₄ + Na₂SiO₃ = Na₂SO₄ + H₂SiO₃;

2HCl + Na₂WO₄ = 2NaCl + H₂WO₄.

Date: 2015-01-12; view: 959