Question

Which of the following reactions are examples of calcination?

• A. ${\mathrm{CaCO}}_3\left(s\right)\to \mathrm{CaO}\left(s\right)+{\mathrm{CO}}_2\left(g\right)$
• B. $4{\mathrm{FeS}}_2\left(s\right)+11O_2\left(g\right)\to 2{\mathrm{Fe}}_2{O}_3\left(s\right)+8{\mathrm{SO}}_2\left(g\right)$
• C. $$ 2\mathrm{Al}{\left(\mathrm{OH}\right)}_3\left(s\right)\to {\mathrm{Al}}_2{O}_3\left(s\right)+3H_{2}O\left(g\right)$\left(\right)$
• D. $$ \mathrm{CuS}\left(s\right)+{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\to 2\mathrm{Cu}\left(s\right)+2{\mathrm{SO}}_2\left(g\right)$\left(\right)$

Answer 1

Answer: (A), (C)

The correct options are
A

${\mathrm{CaCO}}_3\left(s\right)\to \mathrm{CaO}\left(s\right)+{\mathrm{CO}}_2\left(g\right)$

C

$$ 2\mathrm{Al}{\left(\mathrm{OH}\right)}_3\left(s\right)\to {\mathrm{Al}}_2{O}_3\left(s\right)+3H_{2}O\left(g\right)$\left(\right)$

Calcination is a process in which the ore is heated strongly in the absence of air to remove volatile impurities. It involves the thermal decomposition of the ores. This process is mainly used for carbonate and hydroxide ores.
Examples of reaction undergoing calcination among the given are:

${\mathrm{CaCO}}_3\left(s\right)\to \mathrm{CaO}\left(s\right)+{\mathrm{CO}}_2\left(g\right)$

$2\mathrm{Al}{\left(\mathrm{OH}\right)}_3\left(s\right)\to {\mathrm{Al}}_2{O}_3\left(s\right)+3H_{2}O\left(g\right)$