Given that 1 mol of NiCl2.6H2O with excess AgNO3 precipitates 2 mols of AgCl, what is the secondary valence of Ni?

Correct Answer: 6
After the reaction, it will form 2- and 2Cl– in which the former is the coordination complex. There are six water molecules bound to Ni, which makes the secondary valence of Ni as 6.