Explain a vast array of reactions involving precipitation

Question

The qualitative analysis scheme contains a vast array of reactions involving the precipitation, formation of oxidation-reduction and the coordination complexes. Find out each of the following as primarily one of the above kinds of reaction:

a.  2Cr(OH)₄ ^-(aq) + 3H₂O_{2(aq) +}2OH^-(aq)--->2CrO₄ ^2-(aq)+8H₂O(aq)

b. 2Co (OH)₃(s) + H₂O₂(aq)---->2Co(OH)₂(s) + O₂ + 2H₂O
c. Fe(H₂O)₆(aq) + 6F^-(aq) ---->FeF₆^3-(aq) + 6H₂O

d. Zn²⁺(aq) + 4NH₃(aq) -------->Zn(NH₃)₄²⁺(aq)
e. Ni²⁺(aq) + 2NH₃(aq)+2H₂O--->Ni(OH)₂(s) + 2NH₄²⁺ (aq)