Question

Write balanced equations for the formation of [Ni(NH3)6][BF4]2 starting from an anhydrous sample of nickel(II) choride hexahydrate. (3 equations necessary)

I am slightly confused by this. I think the starting sample has the formula [Ni(H20)6]Cl2
Would this react with ammonia?
[Ni(H2O)6]Cl2 + 6NH3 --> [Ni(NH3)6]Cl2 + 6H2O

and then with sodium tetrafluoroborate
[Ni(NH3)6]Cl2 + 2NaBF4 --> [Ni(NH3)6][BF4]2 + 2NaCl

I am not sure how to get three equations.

Answer 1

I am confused by the term anhydrous in the question. My understanding of anhydrous means without water and that means either as an excess of water in the reagent OR no water in the compound. For example, anhydrous HCl is the gas HCl with no water whereas HCl reagent is an aqueous solution of HCl as in HCl(aq).
So do you start with Ni(H2O)6Cl2 or
NiCl2? If it's the latter, then one equation would be the formation of the hexahydrate, the second would be the exchange, as you have it, of NH3 for H2O, and the third would be, as you have it, the NaB4 reaction.