Preparation of sodium nitrite
In iron pan heat the 12 g of sodium nitrate until melted. Then carefully add 30 g of granulated lead.
Heat the reaction mixture and stir about 30 minutes. When adding a lead shield to protect. The melt of these reactions take place:
2NaNO3 --> 2NaNO2 + O2
2Pb + O2 --> 2PbO
4NaNO3 --> 2Na2O + 4NO + 3O2
Na2O + PbO --> Na2PbO2
After cooling the melt vyloužíme hot water and filtered. Yellow lead oxide process to lead nitrate. To the filtrate containing nitrite and olovnatan introduce 2-3 minutes currents of carbon dioxide, which vysrážíme lead carbonate.
The mixture was filtered, the filtrate neutralize few drops of nitric acid, concentrated on a porcelain dish to dryness. The residue přežíhneme in
flame of a Bunsen burner.