31. Which of the following reactions involving magnesium is incorrect? (A) MgC2 + H2O → MgO + C + H2 (B) Mg3N2 + 6 H2O → 3 Mg(OH)2 + 2 NH3 (C) MgH2+2 H2O → Mg(OH)2 + 2 H2 (D) at high temperature, 3 Mg + N2 → Mg3N2 (E) at high temperature, 3 Mg + 2 NH3 → Mg3N2 + 3 H2