Question

Which of the following reactions occur during calcination?

(i) \[\ce{CaCo3 -> CaO + CO2}\]

(ii) \[\ce{2FeS2 + 11/2 O2 -> Fe2O3 + 4SO2}\] 

(iii) \[\ce{Al2O3. {x}H2O -> Al2O3 + {x}H2O}\]

(iv)  \[\ce{ZnS + 3/2 O2 -> ZnO + SO2}\]

Answer 1

(i) \[\ce{CaCo3 -> CaO + CO2}\]

(iii) \[\ce{Al2O3. {x}H2O -> Al2O3 + {x}H2O}\]

Explanation:

Calcination involves heating of the ore below is melting point in the absence of air or in limited supply of air. Oxygen containing ores like oxide, hydroxides and carbonates are calcined. Thus, the following reactions occur during calcination.

\[\ce{CaCO3 ->[Δ] CaO + CO2}\]

\[\ce{Al2O3 * {x}H2O ->[Δ] Al2O3 + {x}H2O}\]