Soda lime can dry neutral or alkaline gases, such as: neutral gases H?, N?, O?, CO; alkaline gas NH?.

Cannot be used to dry acidic gases, such as: CO?, SO?, NO?.

Soda lime is a white or beige powder, loose and porous, composed of calcium oxide (CaO, about 75), water (H?O, about 20), sodium hydroxide (NaOH, about 3) and hydrogen A mixture of potassium oxide (KOH, approximately 1).

Soda lime is mainly used as a desiccant, in which calcium oxide plays a drying role.

Extended information

Common desiccants:

Acidic desiccants: concentrated sulfuric acid (H2SO4), phosphorus pentoxide (P2O5), etc.; mainly dry acidic Or neutral gases such as SO2, CO2, CO, NO2, O2, NO, H2, N2.

Alkaline desiccant: soda lime (CaO), NaOH, etc.; mainly used to dry alkaline or neutral gases, such as NH3, CO, O2, N2, H2, PH3.

Neutral desiccant: CaCl2(s), MgSO4(s), etc.

Another: ①The selection of desiccant depends not only on the properties of the desiccant but also on the properties of the material being dried. For example, concentrated sulfuric acid is an acid, so it cannot dry alkaline gas; in addition, concentrated sulfuric acid also has strong oxidizing properties. , so it cannot be used to dry reducing substances such as H2S, HI, HBr, etc.

② Liquid desiccant is generally installed in a gas scrubber bottle (gas enters from the long tube and exits from the short tube), while solid desiccant is installed in a drying tube or U-shaped tube.