Salts of Ag Cu Cd Zn Co Ni are soluble in ammonia except AgI
So now we have to decide bent b and c
Both are soluble in excess NaOH ..
So now we have to decide by reaction given ..
Idk if both react with air
Fe2+ isnt soluble in excess NaOH i guess
Yep Fe2+ isn't soluble in Naoh.
Fe+2 is probably getting oxidised by air to Fe3+ in first step