Write the reaction equation: P- Ca3P2- PH3- H3PO4- Ca3 (PO4) 2- Ca (HPO4) 2

1) 2P + 3Ca = Ca3P2 (when phosphorus interacts with calcium, calcium phosphide is formed);

2) Ca3P2 + 6H2O = 2PH3 + 3Ca (OH) 2 (when calcium phosphide interacts with water, phosphine and calcium hydroxide are formed);

3) PH3 + 2O2 = H3PO4 (when phosphine interacts with oxygen, phosphoric acid is formed);

4) 2H3PO4 + 3CaO = Ca3 (PO4) 2 + 3H2O (when phosphoric acid interacts with calcium oxide, calcium phosphate and water are formed);

5) Ca3 (PO4) 2 + H3PO4 = 3CaHPO4 (when calcium phosphate interacts with phosphoric acid, calcium hydrogen phosphate is formed).