a)
1. 2Al+2NaOH+6H2O→2Na[Al(OH)4]+3H2↑
2. Na[Al(OH)4]+3HCl→AlCl3+NaOH+3H2O
3. AlCl3+3NaOH→Al(OH)3+3NaCl
4. 2Al(OH)3+3H2SO4→Al2(SO4)3+6H2O
5. Al(OH)3+NaOH→Na[Al(OH)4]
b)
1. B2O3+3Mg→2B+3MgO
2. 2B+N2→2BN
3. BN+3H2O→H3BO3+NH3
4. H3BO3+3HF→BF3+3H2O
5. 4BF3+3H2O→H3BO3+3HBF4
6. 2H2BO3→B2O3+3H2O
c)
1. Tl+NaOH→TlOH+Na
2. 2TlOH+H2SO4→Tl2SO4+2H2O
3. Tl2SO4+H2S→Tl2S+H2SO4
4. 2TlOHTTl2O+H2O
d)
1. 4Al+3O2→2Al2O3
2. Al2O3+3H2SO4→Al2(SO4)3+3H2O
3. Al2(SO4)3+6NaOH→2Al(OH)3+3Na2SO4
4. Al(OH)3+3NaOH→Na3[Al(OH)6]
5. 2Al(OH)3TAl2O3+3H2O