How the product may look alike
1) Reaction of copper (II) ion and ammonia (limited and excess)
2) Reaction between iron (III) ion and KSCN ...
3) Reaction between cobalt(II) ion and potassium cyanide ( limited ans excess)
4) Reaction that occurs when the mixture of Mn2+ , PbO2 and HNO3 ( conc) is heated
Hopefully somebody can help me .