1)FeCl2, FeCl3, PbCl2
2)Mr(P2O3) = 2Ar(P) + 3Ar(O) = 2 х 31 + 3 х 16 = 110
w(P/P2O3) = 2Ar(P)/Mr(P2O3) x 100% = 2 x 31/110 x 100% = 56,36%
Mr(P2O5) = 2Ar(P) + 5Ar(O) = 2 х 31 + 5 х 16 = 142
w(P/P2O5) = 2Ar(P)/Mr(P2O5) x 100% = 2 x 31/142 x 100% = 43,66%