Which oxide among the following is basic?
Basic oxides are formed by metals, especially s-block elements. BaO (group 2) is basic, unlike N₂O₅ (acidic), SiO₂ (acidic), or Al₂O₃ (amphoteric).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity