Write the reaction equation: Ca – CaO – CaCl2 – Ca – CaO – Ca (OH) 2 Ca – Ca (OH) 2

1) 2Ca + O2 = 2CaO (when calcium interacts with oxygen, calcium oxide is formed);

2) CaO + 2HCl = CaCl2 + H2O (when calcium oxide interacts with hydrochloric acid, calcium chloride and water are formed);

3) CaCl2 = Ca + Cl2 (during electrolysis, calcium chloride decomposes into calcium and chlorine);

4) 2Ca + H2O = CaO + CaH2 (when calcium interacts with water, calcium oxide and calcium hydride are formed);

5) CaO + H2O = Ca (OH) 2 (when calcium oxide interacts with water, calcium hydroxide is formed);

6) Ca + 2H2O = Ca (OH) 2 + H2 (when calcium interacts with water, calcium hydroxide and hydrogen are formed).