a)
(1) \(2Al+3FeCl_2\rightarrow2AlCl_3+3Fe\)
(2) \(2Fe+3Cl_2\underrightarrow{t^o}2FeCl_3\)
(3) \(FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3\downarrow+3NaCl\)
(4) \(2Fe\left(OH\right)_3\underrightarrow{t^o}Fe_2O_3+3H_2O\)
b)
(1) \(2Cu+O_2\underrightarrow{t^o}2CuO\)
(2) \(CuO+2HCl\rightarrow CuCl_2+H_2O\)
(3) \(CuCl_2+2AgNO_3\rightarrow Cu\left(NO_3\right)_2+2AgCl\downarrow\)
(4) \(Cu\left(NO_3\right)_2+2NaOH\rightarrow Cu\left(OH\right)_2\downarrow+2NaNO_3\)
(5) \(Cu\left(OH\right)_2\underrightarrow{t^o}CuO+H_2O\)
(6) \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)