If an excess of $NH_4OH$ is added to a $CuSO_4$ solution,it forms a deep blue coloured complex which is:

The cation that does not form an amine complex with excess of ammonia is

Which of the following complexes is the most stable: $[Fe(H_2O)_6]^{3+}$,$[Fe(CN)_6]^{3-}$,$[Fe(C_2O_4)_3]^{3-}$,or $[FeCl_6]^{3-}$?

The molecular formula of a cobalt coordination complex contains five ammonia molecules,one nitro group,and two chlorine atoms for one cobalt atom. In an aqueous solution,one mole of the substance produces $3$ moles of ions. Upon reacting this solution with an excess of silver nitrate solution,$2$ moles of $AgCl$ precipitate are obtained. What is the ionic formula of the complex?

The colour of cobalt chloride solution is:

The reaction of $Pb(NO_3)_2$ and $NaCl$ in water produces a precipitate that dissolves upon the addition of $HCl$ of appropriate concentration. The dissolution of the precipitate is due to the formation of