(i) Na2B4O7.10H2O + (- 10H2O) → Na2B4O7 → 2NaBO2 + B2O3
(ii) 2AI + 2NaOH + 2H2O → 2NaAIO2 + 3H2
(iii) Na2B4O7.10H2O + (- 10H2O) → Na2B4O7 → 2NaBO2 + B2O3
B2O3 + CoO → Co(BO2)2
(iv) AIN + 3H2O → AI(OH)3 + NH3
(v) Nitric acid whether dilute or concentrated hardly affects aluminium at all. Aluminium is rendered passive. A thin film of Al2O3 is formed on the surface of the metal.