Question

$\text{A}$ is an ore of two metals which undergoes calcination and forms calcium oxide, magnesium oxide and carbon dioxide.​​​
Identify $\text{A}$ from the following options.

• A. ${\mathrm{CaCO}}_2.{\mathrm{MgSO}}_4$
• B. ${\mathrm{MgCO}}_3.{\mathrm{CO}}_2$
• C. ${\text{CaCO}}_3.{\mathrm{MgCO}}_3$
• D. ${\mathrm{CaSO}}_4.{\mathrm{MgCO}}_3$

Answer 1

The correct option is C ${\text{CaCO}}_3.{\mathrm{MgCO}}_3$

Calcination is a process in which the ore is heated strongly in the absence of air to remove volatile impurities. It thermally decomposes the carbonate.
A is${\mathrm{CaCO}}_3.{\mathrm{MgCO}}_3$${\mathrm{CaCO}}_3.\mathrm{MgC}{O}_3\left(s\right)\stackrel{\mathrm{Calcination}}{\to }\mathrm{CaO}\left(s\right)+\mathrm{MgO}\left(s\right)+2{\mathrm{CO}}_2\left(g\right)$

${\mathrm{CaCO}}_3.{\mathrm{MgCO}}_3$ is called dolomite and is potentially an ore of both the metals $\mathrm{Ca}$and $\mathrm{Mg}$.