2 P0 + 2 NaOHI + 6 H2IO 2 Na[PIII(OHI)4] + 3 H20

This is a complexation reaction: Na[P(OH)4] is the formed complex.

This is an oxidation-reduction (redox) reaction:

2 P0 - 6 e- 2 PIII (oxidation)

6 HI + 6 e- 6 H0 (reduction)

Change the oxidation states