2 CrIII(OH)3 + 3 Ag2IO + 4 NaOH 6 Ag0 + 2 Na2CrVIO4 + 5 H2O

This is an acid-base reaction (neutralization): Cr(OH)3 is an acid, NaOH is a base.

This is an oxidation-reduction (redox) reaction:

6 AgI + 6 e- 6 Ag0 (reduction)

2 CrIII - 6 e- 2 CrVI (oxidation)

Change the oxidation states