H2SeIVO3 + 2 Zn0 + 4 HCl 2 ZnIICl2 + Se0 + 3 H2O

This is an oxidation-reduction (redox) reaction:

SeIV + 4 e- Se0 (reduction)

2 Zn0 - 4 e- 2 ZnII (oxidation)

H2SeO3 is an oxidizing agent, Zn is a reducing agent.