Answer the following question given this paragraph: 

A solution of cobalt chloride in water is pink due to the presence of the solvated Co 2+ ion. If sufficient HCl is added, the solution turns blue as the CoCl 4 2- ion forms. The reaction can be shifted back to the pink form if more water is added to the solution.


Q: What causes cobalt chloride to turn pink?


A:
co 2+ ions