Question

Calcination is used in metallurgy to remove
(A) ${{H}_{2}}O$ and ${{H}_{2}}S$
(B) ${{H}_{2}}O$ and $C{{O}_{2}}$
(C) $C{{O}_{2}}$and ${{H}_{2}}S$
(D) None of these

Answer 1

Hint: Calcination is the process of heating ore to a high temperature and turning it into an oxide. In this process, the ore is heated below the melting point in the presence of little or no air. The disintegration takes place close to or above the thermal decomposition temperature, that is, the temperature at which the standard Gibbs free energy of a specific calcination reaction equals zero. High-temperature heating helps oxidise any mass of the substance while also removing volatile components. As a result, metals can be purified through the process of calcination.

Complete Step by Step Answer:
Carbonate ores are thermally broken down during calcination. This transforms the metal carbonates into metal oxides and carbon dioxide. This ore does not react when heated in the presence of oxygen or air, making the entire procedure pointless.

Limestone (calcium carbonate) is mostly broken down by calcination into carbon dioxide and lime (calcium oxide).
$CaCO_3\rightarrow CaO + CO_2$
This process can also be used to convert hydrated iron oxide ($F{{e}_{2}}{{O}_{3}}.x{{H}_{2}}O$) into anhydrous iron oxide ($F{{e}_{2}}{{O}_{3}}$) and water.
$Fe_2O_3.xH_2O\rightarrow Fe_2O_3 + xH_2O$
Thus, Calcination is used in metallurgy to remove ${{H}_{2}}O$ and $C{{O}_{2}}$.
Correct Option: (B) ${{H}_{2}}O$ and $C{{O}_{2}}$

Note: Impurities such as moisture and volatile chemicals are eliminated during the process of calcination. Calcination is a Latin word that means burning lime. Usually, calcination is done in a reverberating furnace. It is useful for the thermal decomposition of oxide and carbonate ores.