In 2KBr + 3H₂SO₄ + 2MnO₂ → Br₂ + 2MnSO₄ + 2H₂O + K₂SO₄, which element undergoes the largest increase in oxidation number
Br (-1 in KBr) to 0 in Br₂: +1. Mn (+4 in MnO₂) to +2: -2. Br increases, Mn decreases; Br has the largest increase.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Types of Redox Reactions - Combination Decomposition Displacement