Ans: Zinc sulphide on heating in presence of air forms zinc oxide and sulphur dioxide.
ZnS + 3 O₂ + heat → 2 ZnO + 2 SO₂
In calcination process the carbonate ore is heated strongly in the
absence of air to convert it into metal oxide. As obtaining metal from
metal oxide is easy process.
ZnCO₃ (on calcination) → ZnO + CO₂