Zinc oxide reacts with both NaOH and HCl, thus it is called ________.
Amphoteric oxide
Since Zinc oxide is reacting with both acid and base, it is an amphoteric oxide(oxides which react both with acids and bases)
ZnO + 2 NaOH + H2O → Na2[Zn(OH)4]
ZnO + 2HCl → ZnCl2 + H2O.