Consider two chemical reactions (A) and (B) that take place during metallurgical process :
(A) $\mathrm{ZnCO}_{3(\mathrm{~s})} \stackrel{\Delta}{\longrightarrow} \mathrm{ZnO}_{(\mathrm{s})}+\mathrm{CO}_{2(\mathrm{~g})}$
(B) $2 \mathrm{ZnS}_{(\mathrm{s})}+3 \mathrm{O}_{2(\mathrm{~g})} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{ZnO}_{(\mathrm{s})}+2 \mathrm{SO}_{2(\mathrm{~g})}$
Correct Option: 1
(A) $\mathrm{ZnCO}_{3}$ (S) $\stackrel{\Delta}{\longrightarrow} \mathrm{ZnO}$ (s) $+\mathrm{CO}_{2}$ (g)
Heating in absence of oxygen in calcination.
(B) $2 \mathrm{Zns}(\mathrm{s})+3 \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{ZnO}(\mathrm{g})+2 \mathrm{SO}_{2}(\mathrm{~g})$
heating in presence of oxygen in roasting
Hence (A) is calcination while (B) in roasting.