$\begin{array}{1 1}(A)\;[Mg(H_2O)_6]^{2+}+(EDTA)^{4-}\quad\underrightarrow{\text{excess NaOH}}\quad [Mg(EDTA)]^2+6H_2O\\(B)\;CuSO_4+4KCN\rightarrow K_2[Cu(CN)_4]+K_2SO_4\\(C)\;Li_2O+2KCl\rightarrow 2LiCl+K_2O\\(D)\;[CoCl(NH_3)_5]^++5H^+\rightarrow Co^{2+}+5NH_4^++Cl^-\end{array} $
