JEE Main · 2026 · 22 Jan 2026 · Shift 2 · d and f Block Elements

A mixed oxide contains the same metal in two different oxidation states. Among the oxides given, $\mathrm{M}{\mathrm{n}}_3{\mathrm{O}}_4$ ($\mathrm{MnO}\cdot \mathrm{M}{\mathrm{n}}_2{\mathrm{O}}_3$, Mn as $+2$ and $+3$), $\mathrm{F}{\mathrm{e}}_3{\mathrm{O}}_4$ ($\mathrm{FeO}\cdot \mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$, Fe as $+2$ and $+3$) and $\mathrm{C}{\mathrm{o}}_3{\mathrm{O}}_4$ ($\mathrm{CoO}\cdot \mathrm{C}{\mathrm{o}}_2{\mathrm{O}}_3$, Co as $+2$ and $+3$) are mixed oxides, whereas $\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_3,{\mathrm{V}}_2{\mathrm{O}}_4,\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_3$ and $\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$ each hold the metal in a single oxidation state. The number of mixed oxides is $3$.