$\begin{array}{1 1} (a)\;(i) 3Cl_2+6NaOH(conc) \to 5NaCl +NaClO_4 +3H_2O_2(ii)2Fe^{3+}+SO_2+2H_2O \to 2Fe^{3+}+SO_4^{3-}+4H^{+} \\ (b)\;(i) 3Cl_2+6NaOH(conc) \to 5NaCl +NaClO_3 +3H_2O(ii)2Fe^{3+}+SO_2+2H_2O \to 2Fe^{2+}+SO_4^{2-}+4H^{+} \\ (c)\;(i) 3Cl_2+6NaOH(conc) \to 5NaCl +NaClO_3 +H_2O (ii)2Fe^{3+}+SO_2+2H_2O \to 2Fe^{2+}+SO_2^{2-}+3H^{+} \\(d)\;(i) 3Cl_2+6NaOH(conc) \to 4NaCl +NaClO_3 +2H_2O (ii)2Fe^{3+}+SO_2+2H_2O \to Fe^{2+}+SO_4^{2-}+3H^{+} \end{array} $