Difference Between Disproportionation and Redox

The key difference between disproportionation and redox is that in disproportionation reactions, the same reactant undergoes oxidation and reduction. But, in redox reactions, two different reactants usually undergo oxidation and reduction.

Furthermore, disproportionation is a chemical reaction where a molecule is transformed into two or more dissimilar products while redox reaction is a type of chemical reaction in which oxidation and reduction half-reactions occur simultaneously. Above all, disproportionation is a type of redox reaction because there are two simultaneous oxidation and reduction reactions.

CONTENTS

1. Overview and Key Difference
2. What is Disproportionation
3. What is Redox
4. Side by Side Comparison – Disproportionation vs Redox in Tabular Form
5. Summary

What is Disproportionation?

Disproportionation is a chemical reaction where a molecule is transformed into two or more dissimilar products. Fundamentally, it is a type of redox reaction where the same molecule undergoes both oxidation and reduction. Furthermore, the reverse of this reaction is called comproportionation. The general form of these reactions is as follows:

2A ⟶ A’  +   A”

Furthermore, some common examples for this type of reactions are as follows

• Conversion of hydrogen peroxide into water and oxygen

2H₂O₂ ⟶ H₂O  +  O₂

• Disproportionation of mercury(I) chloride

Hg₂Cl₂ → Hg + HgCl₂

• Disproportionation of phosphoric acid into phosphoric acid and phosphine

4 H₃PO₃ → 3 H₃PO₄ + PH₃

• Disproportionation of bromine fluoride gives bromine trifluoride and bromine

3 BrF → BrF₃ + Br₂

What is Redox?

Redox reaction is a type of chemical reaction in which oxidation and reduction half-reactions occur simultaneously. Moreover, in this reaction, we consider oxidation and reduction as complementary processes. Here, oxidation is the loss of electrons or increase in the oxidation state while reduction is the gain of electrons or decrease of oxidation state.

Furthermore, the rate of a redox reaction can vary from very slow processes such as rusting to rapid processes such as fuel burning.

What is the Difference Between Disproportionation and Redox?

The key difference between disproportionation and redox is that in disproportionation reactions the same reactant undergoes oxidation and reduction, whereas, in redox reactions, two different reactants usually undergo oxidation and reduction. Considering some examples, disproportionation includes disproportionation of mercury(I) chloride to form mercury and mercury(II) chloride, disproportionation of bromine fluoride to form bromine trifluoride and bromine, etc. whereas rusting, combustion, fuel burning, etc. are examples for redox reactions.

The below infographic summarizes the difference between disproportionation and redox.

Summary – Disproportionation vs Redox

Disproportionation is a chemical reaction where a molecule is transformed into two or more dissimilar products while redox reaction is a type of chemical reaction in which oxidation and reduction half-reactions occur simultaneously. The key difference between disproportionation and redox is that in disproportionation reactions the same reactant undergoes oxidation and reduction, whereas in redox reactions, usually, two different reactants undergo oxidation and reduction.

Reference:

1. Helmenstine, Anne Marie. “Disproportionation Definition in Chemistry.” ThoughtCo, Aug. 6, 2019, Available here.

Image Courtesy:

1. “Disproportionation of toluene” By Warrenjlange – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Rust screw” By User:Paulnasca – Own work (CC BY 2.0) via Commons Wikimedia