In 2K₂Cr₂O₇ + 2H₂O + 3S → 4KOH + 2Cr₂O₃ + 3SO₂, which element undergoes the largest decrease in oxidation number?
Cr (+6 in Cr₂O₇²−) to +3 in Cr₂O₃: -3. S (0) to +4 in SO₂: +4. Cr decreases most.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Applications of Redox Reactions and Disproportionation