Which of the given reactions is not an example of disproportionation reaction?

Which of the given reactions is not an example of disproportionation reaction?
  1. 2H2O22H2O+O2
  2. 2NO2+H2OHNO3+HNO2
  3. MnO4-+4H++3e-MnO2+2H2O
  4. 3MnO4+2-4H+2MnO4+-MnO2+2H2O

Solution

Disproportionation reaction, is a type of redox reaction involving simultaneous reduction and oxidation of atoms of the same element from one oxidation state (OS) to two different oxidation states.

2H2O2-12H2O-2+O20 : Disproportionation

2NO2+H2OHNO3+HNO2 : Disproportionation

MnO4-+4H++3e-MnO2+2H2O : reduction only

3MnO42-+4H+2MnO4-+MnO2+4+2H2O : Disproportionation

Asked in: JEE Main 2022 (26 Jul Shift 1)

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