A sample of hydrated cobalt (II) chloride (CoCl₂) has a mass of 5.22 g.
When it is dehydrated, the anhydrous compound has a mass of 2.85 g.
What is the correct chemical formula for the hydrate?
1. CoCl₂· 4H₂O
2. CoCl₂· 6H₂O
3. CoCl₂· 8H₂O