Final answer:
MnO is basic because it forms hydroxide ions when reacting with water, while Mn₂O₇ is acidic as it can release protons into the solution.
Step-by-step explanation:
The student is asking why Mn₂O₇ is acidic, while MnO is basic. Generally, metal oxides react with water to produce basic solutions. Manganese(III) oxide, Mn₂O₃, is basic because manganese is in the +3 oxidation state and can react with water to form hydroxide ions.
In contrast, manganese(VII) oxide Mn₂O₇ is acidic because it can react with water to release protons (H+). The basicity or acidity of oxides is related to the oxidation states of the central metal atom; higher oxidation states typically lead to more acidic oxides.