\begin{aligned} &\text { Cobalt nitrate test }\\ &\mathrm{MCO}_3 \rightarrow \mathrm{MO} \xrightarrow[+\Delta]{\mathrm{Co}\left(\mathrm{NO}_3\right)_2} \mathrm{CoO} . \mathrm{MO} \end{aligned} Flame test
$$ \mathrm{MCO}_3 \rightarrow \mathrm{MCl}_2 \rightarrow \mathrm{M}^{2+} $$
Borax Bead test
$$ \mathrm{MSO}_4 \underset{\Delta}{\stackrel{\mathrm{Na}_2 \mathrm{~B}_4 \mathrm{O}_7}{\rightarrow}} \mathrm{M}\left(\mathrm{BO}_2\right)_2 \rightarrow \mathrm{MBO}_2 \rightarrow \mathrm{M} $$
\begin{aligned} &\text { Charcoal cavity test }\\ &\mathrm{MSO}_4 \underset{\Delta}{\stackrel{\mathrm{Na}_2 \mathrm{CO}_3}{\rightarrow}} \mathrm{MCO}_3 \rightarrow \mathrm{MO} \rightarrow \mathrm{M} \end{aligned}