\(2Al+3O_2\underrightarrow{^{^{t^o}}}2Al_2O_3\)
\(Al_2O_3+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2O\)
\(Al_2\left(SO_4\right)_3+3BaCl_2\rightarrow2AlCl_3+3BaSO_4\)
\(AlCl_3+3NaOH\rightarrow Al\left(OH\right)_3+3NaCl\)
\(2Al\left(OH\right)_3\underrightarrow{^{^{t^o}}}Al_2O_3+3H_2O\)
\(2NaOH+Al_2O_3\rightarrow2NaAlO_2+H_2O\)