Chemistry - Complete d-block Question with Solution | TestHub

 All the metals except scandium form MO oxides, which are ionic. ${\mathrm{Mn}}_2{\mathrm{O}}_7$ is a covalent green oil.  In vanadium there is gradual change from the basic ${\mathrm{V}}_2{\mathrm{O}}_3$ to less basic ${\mathrm{V}}_2{\mathrm{O}}_4$ and to amphoteric ${\mathrm{V}}_2{\mathrm{O}}_5$ . ${\mathrm{V}}_2{\mathrm{O}}_4$ dissolves in acids to give ${\mathrm{VO}}^{2+}$ salts. Similarly, ${\mathrm{V}}_2{\mathrm{O}}_5$ reacts with alkalies as well as acids to give ${\mathrm{VO}}_4^{3-}$ and ${\mathrm{VO}}_4^{+}$ respectively. The well characterised $\mathrm{CrO}$ is basic but ${\mathrm{Cr}}_2{\mathrm{O}}_3$ is amphoteric.

(A) ${\mathrm{Mn}}_2{\mathrm{O}}_7$ is green oil at room temperature.

(B) ${\mathrm{V}}_2{\mathrm{O}}_4$ dissolve in acids to give $V{O}^{2+}$ salts.

(C) $\mathrm{CrO}$ is basic oxide.

Hence option B is the answer,