why add cons. HCl in systhesis of [Co(NH3)6]³* ? 3+

1. What is the balanced net ionic equation for the equilibrium involving complex ions, CoCL42- and [Co(H2O)6]2+. 2. When heating the mixture the color was blue and when cooled it was pink. Based on this, is the forward reaction endothermic or exothermic and why? What is the balanced net ionic equation when heat is included?  3. How could an alcohol solution of CoCL2 beused to predict rain?

1. Calculate the concentration of Zn²* in a 0.30M solution of [Zn(CN)4]². Kr[Zn(CN)4] ² = 1 x 1019 2-

Write the reactions of formation of [Cu(NH3)4]Cl2 and its destruction in excess of HNO3