sometimes gasses need to be dried before use

Drying AgentExample(s)Notes
Concentrated sulfuric acid
Most gasses, including:
- Chlorine
- Hydrogen Chloride

Acidic gasses
Method is not suitable for gasses that react with sulfuric acid
Quicklime (calcium oxide)
Ammonia

Alkaline gasses
Calcium oxide absorbs moisture and carbon dioxide from air → so it must be freshly heated before use

method cannot be used to dry gasses that react with calcium oxide (eg: carbon dioxide)
Fused calcium chloride
Hydrogen, Nitrogen, Carbon dioxide

Good for most gasses
Calcium chloride readily absorbs moisture from air → so it must be heated before use

method cannot be used to dry gasses which react with calcium chloride.
→ must state “pass it through”