$\begin{array}{1 1} \text{The order of their acidity is} H_3PO_4 > H_3PO_3 > H_3PO_2 \\ \text{All of them are reducing is nature} \\ \text{All of them are tribasic acids} \\ \text{The geometry of phosphours is tetrahedral in all the three } \end{array} $