How to judge whether potassium hydroxide is expired?

Chemical formula of potassium hydroxide: Koh, its solid appearance is white powder or flake, with strong alkalinity and corrosiveness, easy to dissolve in water, easy to absorb moisture in the air to deliquesce or absorb carbon dioxide to generate potassium carbonate, so it can be used as desiccant, absorbent, etc.

To judge whether potassium carbonate has been generated in the solution, we only need to take a small number of samples and test with some reagents, such as dilute hydrochloric acid and limestone. Because potassium carbonate belongs to carbonate, it can react with dilute hydrochloric acid to generate carbon dioxide gas, and potassium carbonate can react with calcium hydroxide to generate calcium carbonate precipitation and potassium hydroxide. When testing, we need to observe whether there is gas or precipitation in the solution Lake formation.

To keep it for a long time, it should be stored in a cool, dry and well-ventilated warehouse, away from the fire and heat source. The humidity in the warehouse shall be less than 85% to avoid solution failure.