What happens when white vitrol is heated ?

Show that zinc white is an amphoteric substance.
Zinc oxide is amphoteric because it reacts with both acids and bases to form salts.
Reactions:
ZnO + 2HCl → ZnCl2 + H2O
(Zinc chloride)
2NaOH + ZnO → Na2ZnO2 + H2O
(Sodium zincate)