Question

Znco3 is heated in absence of air

Answer 1

When zinc carbonate is heated in absence of air leaves zinc oxide and gives out carbon-dioxide. This process is also called calcination.

ZnCo3⇒Zno+Co2

Answer 2

When zinc carbonate is heated in limited air, it gives Zinc oxide and carbon dioxide. This process is called calcination.

ZnCO3----------->ZnO+CO2