NATRIUM (SODIUM) - Na
Propertiesof sodium Na:
An alkali metal. A silvery-white (in a thin layer - with a purple tint), lightweight, very soft, low melting. Dark red sodium vapor is composed of atoms Na (predominant) and molecules Na2. Under special conditions is formed a violet-blue colloidal solution of sodium in ether. Chemically dissolves in liquid NH3 (blue solution), molten NaOH. Very reactive, air-covered oxide film (tarnish), ignited at a moderate heat. Stable in an atmosphere of argon and nitrogen. A strong reducing agent, reacts vigorously with water, acids, non-metals. With nitrogen only reacts when heated (as opposed to Li). With the mercury forms an amalgam, amalgam - a strong reducing agent, but (in contrast to the pure sodium), the reaction with water flowing quietly.
Does not react with air, is well preserved under a layer of gasoline or kerosene, is easily suspended in boiling inert solvents (toluene, xylene, heptane, octane, etc.). In an inert atmosphere, the molten sodium is rapidly distributed over the surface of certain solids (NaCl, Na2CO3, coal, iron, Al2O3, SiC, ZrO2), forming a gray-black monatomic coverage. Сolors the flame of a gas burner in yellow. The most widespread metal in seawater.
| Molar mass | g/mol | 22.99 |
| Density in solid state | g/cm3 | 0.968 |
| Melting point | °C | 97.83 |
| Boiling point | °C | 886 |
Obtaining sodium Na:
4 NaOH (liquid) →Electrolysis 4Na (cathode) + O2↑ (anode) + 2H2O.
Na2CO3 + 2C(coke) = 2Na + 3CO (900-1000°C).
2NaCl (liquid) →Electrolysis 2Na (cathode) + Сl2↑ (anode).
2NaCl + 2H2O →Electrolysis→ H2↑ (cathode) + Сl2↑ (anode) + 2NaOH.
2NaCl (melt) (on Hg-cathode)→Electrolysis 2Na (cathode) + Сl2↑ (anode).
Reactions with sodium Na:
2Na + 2 H2O = 2 NaOH + H2↑.
2Na + 2 HСl (diluted) = 2 NaCl + H2↑.
2Na + 2 NaOH = 2 Na2O + H2 (600°C).
2Na + H2 = 2 NaH (250-400°C, pressure).
2Na + O2 (air) = Na2O2 (burning, impurity Na2O)
2Na + O2 = Na2O2 (250-400°C).
4Na + O2 + 2 H2O = 4 NaOH.
2Na + E2 = 2 NaE (normal temp., E = F, Cl; 150-250°C, E = Вr, I).
2Na + E = Na2E (t>130° С, E = S, Se, Те),
2Na + nS = Na2(Sn) [-40° С, in the liquid NH3, n = 1, 2, 4, 5].
6Na + N2 = 2 Na3N (100° С, electric discharge),
3Na + P (red) = Na3P (green) [200°C, in the atmosphere of Аr].
2Na + 2C (graphite) = Na2C2 (150-200°C).
2Na + 2H2S (saturated) = 2NaHS↓ + H2↑ (in benzene).
Na + 4NH3(liquid) = [Na(NH3)4] (blue) (at - 40°C),
[Na(NH3)4] + nNH3(liquid) ↔ [Na(NH3)4]+ + e- - nNH3.
2Na + 2NH3(gas) = 2NaNH2 + H2 (350°C).
2Na + B2O3 + 7H2 = 2Na[BH4] + 3H2O (250-300°C).
