Question

Al - Al2O3 - Na[Al(OH)4] - Al(OH)3 - Al2O3 - Al

Answer 1

2Al+3O2=2Al2O3
Al2O3+2NaOH+3H2O=2Na[Al(OH)4] 
Na[Al(OH)4]=Al(OH)3+NaOH
2Al(OH)3 = Al2O3 +3H2O
2Al2O3=4Al+3O2

Answer 2

4Al + 3O2 -> 2Al2O3
Al2O3 + 2NaOH + 3H2O -> 2Na[Al(OH)4)]
Na[Al(OH)4] + HCl -> Al(OH)3 + NaCl + H2O
2Al(OH)3 -> Al2O3 + 3H2O
Al2O3 +3 H2 -> 2Al + 3H2O