Question

Calcination is used in metallurgy for the removal of?

• A. H₂O and H₂S
• B. CO₂ and H₂S
• C. H₂O and CO₂
• D. Water and Sulphide.

Answer 1

The correct option is C

H₂O and CO₂

The explanation for the correct option

1. Calcination is a process in which ore (Mainly carbonate) is heated at a high temperature in the limited supply of air to remove volatile substances, leaving behind the metal oxide.
2. For example, when zinc carbonate (${\mathrm{ZnCO}}_3$) is heated in the absence of oxygen, it gets converted into zinc oxide ($\mathrm{ZnO}$). $$\begin{gathered} {\mathrm{ZnCO}}_3\left(\mathrm{s}\right)\stackrel{∆}{\to }\mathrm{ZnO}\left(\mathrm{s}\right)+\mathrm{CO}2\left(\mathrm{g}\right) \\ \mathrm{Zinc}\mathrm{Zinc}\mathrm{oxide}\mathrm{Carbon} \\ \mathrm{carbonate}\mathrm{dioxide} \end{gathered}$$

3. The other example that we can take is the heating of rust

$$\begin{gathered} {\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{XH}}_2\mathrm{O}\stackrel{∆}{\to }{\mathrm{Fe}}_2{\mathrm{O}}_3+{\mathrm{XH}}_2\mathrm{O} \\ \mathrm{Rust}\mathrm{Iron}\left(\mathrm{II}\right)\mathrm{oxide}\mathrm{Moisture} \end{gathered}$$

4. From the above example, it is clear that CO₂ and H₂O are volatile substance, which gets removed during calcination.

The explanation for the incorrect option.

Since calcination process is used to remove volatile substances like CO₂ and H₂O only. Therefore other options are incorrect.

Conclusive statement- option (C) is correct.