a)
\(Al+\dfrac{3}{2}Cl_2\rightarrow AlCl_3\\ AlCl_3+3NaOH\rightarrow Al\left(OH\right)_3+3NaCl\\ 2Al\left(OH\right)_3\underrightarrow{t^o}Al_2O_3+3H_2O\\ Al_2O_3\xrightarrow[criolic]{đpnc}2Al+\dfrac{3}{2}O_2\)
b)
\(Fe+\dfrac{3}{2}Cl_2\rightarrow FeCl_3\\ FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3+3NaCl\\ 2Fe\left(OH\right)_3\underrightarrow{t^o}Fe_2O_3+3H_2O\\ Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)