Preparation of sodium metabisulphite h1>
Into frit placed sodium bicarbonate (baking soda) and shank are bringing the bottom frit of carbon dioxide. Carbon dioxide do not dry, humidity contrary, accelerates the reaction. resulting sulfite contains moisture and residues bicarbonate. The preparation can be dried in a desiccator.
2NaHCO3 + 2SO2 --> Na2S2O5 + H2O + 2CO2
Place the frit glass tube was used to seal the glass wool (untested)