\(\underset{1 \text { mole }}{ H _{2} PO _{2}^{-}}+\underset{\text { excess }}{+4 Ag ^{+}}+2 H _{2} O \rightarrow \underset{4 \text { mole }}{4 Ag +} H _{3} PO _{4}+3 H ^{+}\)
$SF _{4}, BF _{4}^{-}, CIF _{3}, AsF _{3}, PCl _{5}, BrF _{5}, XeF _{4}, SF _{6}$