Which reaction involves a redox process where a single element acts as both oxidizing and reducing agent?
In 3HNO₂ → HNO₃ + 2NO + H₂O, N (+3) in HNO₂ is oxidized to +5 in HNO₃ and reduced to +2 in NO, a disproportionation.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Oxidizing and Reducing Agents and Strength