Editing Cobalt(II) chloride (section)

== Moisture indication ==
[[File:Blue silica gel.jpg|left|thumb|The deep blue colour of this moisture indicating [[silica gel]] is due to cobalt chloride. When hydrated the colour changes to a light pink/purple.]]
Cobalt chloride is a common visual moisture indicator due to its distinct colour change when hydrated. The colour change is from some shade of blue when dry, to a pink when hydrated, although the shade of colour depends on the substrate and concentration. It is impregnated into paper to make test strips for detecting moisture in solutions, or more slowly, in air/gas. [[Desiccant]]s such as [[silica gel]] can incorporate cobalt chloride to indicate when it is "spent" (i.e. hydrated).<ref>{{Cite journal|last=Solomon|first=M. E.|date=February 1945|title=The use of cobalt salts as indicators of humidity and moisture|url=https://onlinelibrary.wiley.com/doi/10.1111/j.1744-7348.1945.tb06763.x|journal=Annals of Applied Biology|language=en|volume=32|issue=1|pages=75–85|doi=10.1111/j.1744-7348.1945.tb06763.x|issn=0003-4746|url-access=subscription}}</ref>