Thus, Mn2O7 gives HMnO4 and CrO3 gives H2CrO4 and H2Cr2O7 V2O5 is, however, amphoteric though mainly acidic and it gives VO4
3– as
well as VO2
+ salts In vanadium there is gradual change from the basic
V2O3 to less basic V2O4 and to amphoteric V2O5 V2O4 dissolves in acids
to give VO
2+ salts