a) 1) To obtain copper chloride from copper oxide, it is necessary to add hydrochloric acid to the oxide:
CuO + 2HCl → CuCl2 + H2O;
2) As a result of the exchange reaction of copper chloride and sodium hydroxide, we get – sodium chloride and copper hydroxide (II):
CuCl2 + 2NaOH → 2NaCl + Cu (OH) 2 ↓;
3) When heated, copper (II) hydroxide decomposes into copper (II) oxide and water:
Cu (OH) 2 ↓ → CuO + H2O.
b) 1) Magnesium reacts with oxygen, and we get – magnesium oxide:
2Mg + O2 → 2MgO;
2) To obtain magnesium chloride from its oxide, it is necessary to add hydrochloric acid to the oxide:
MgO + 2HCl → MgCl2 + H2O;
3) Magnesium chloride reacts with sodium hydroxide and forms – magnesium hydroxide and sodium chloride:
MgCl2 + NaOH → Mg (OH) 2 + NaCl.
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