Answer 1

Magnesium does not react with cold water.
 (i) However, it reacts with steam rapidly to form magnesium hydroxide and hydrogen gas.
       Mg(s) + H₂O(g) →  Mg(OH)₂(aq)  + H₂(g)

(ii) Magnesium reacts very rapidly with steam to form magnesium oxide and hydrogen gas.
  Mg(s) + H₂O(g) →  MgO(s)  +  H₂(g)