Question

Explain how (in procedures step format), the reaction of Ni(OH)2 with NH3 would enable you to separate a mixture of iron(III) and nickel(II) hydroxide.

I need help with question a but can you tell me if my answer is right for b Thank you (a. has to be in procedures step format, I am confused about this can I have easy to follow steps. thanks again

b Explain why you can dissolve Ni(OH)3 in aqueous ammonia. The compound Ni(OH)2 is very much soluble in ammonia, since it will form a complex precipitate.

Answer 1

Solution:

Ni(OH)₂ (s) + 6 NH₃ (aq) --> [Ni(NH₃)₆]²⁺ (aq) + 2 (OH^-) (aq)

The above is the balance equation for the given reactants and forms the soluble complex of [Ni(NH₃)₆]²⁺ , when the mentioned reactants are used in separation of iron(III) resuls in formation of insoluble complex precipitate with soluble aqueous layer of nickel (II) hydroxide.

The complex Ni(OH)₂ is easily dissolvable in solution even if it forms precipitate, the effect is due to the capability of electron transfering OH- ions to the solution, which favors the easy dissociation of the atom/ molecules.