a. Blue cobalt chloride paper gets its blue colour from [CoCl₄]^2– ions. What is the oxidation number of the cobalt in this complex ion?

b. Blue cobalt chloride paper is used to test for water. If water is present the paper turns pink as a complex forms between the cobalt ion and six water ligands (Figure 24.12). Write an equation to show the ligand substitution reaction that takes place in a positive test for water.

Transcribed Image Text:

Figure 24.12 A positive test for the presence of water using anhydrous cobalt chloride paper.