Question

P→Ca3P2→PH3→P2O5→H3P4→Ca3(PO4)→P2O5

Answer 1

P->Ca3P2->PH3->P2O5->H3PO4->Ca3(PO4)2->P2O5

3 Ca+2 P = Ca3P2

Ca3P2+ 6 H2O = 3 Ca(OH)2+2 PH3

2 PH3+ 4 O2 = P2O5+3 H2O

P2O5+ 3 H2O = 2 H3PO4

2 H3PO4 + 3 CaO = Ca3(PO4)2 + 3 H2O

Ca3(PO4)2 + 3 H2O = P2O5 + 3 Ca(OH)2