The key difference between metathesis and redox reactions is that in metathesis reactions, the exchange of two ionic species between two molecules occurs whereas, in redox reactions, the exchange of electrons between two chemical species occurs.
Metathesis and redox reactions are two types of chemical reactions. But they have different mechanisms of action. Metathesis is a single-step reaction, whereas a redox reaction has two parallel half-reactions required for the electron exchange process.
CONTENTS
1. Overview and Key Difference
2. What is Metathesis
3. What are Redox Reactions
4. Similarities Between Metathesis and Redox Reactions
5. Side by Side Comparison – Metathesis vs Redox Reactions in Tabular Form
6. Summary
What is Metathesis?
Metathesis or double displacement reactions are a type of chemical reaction in which an exchange of two ionic species between two molecules occurs. The general formula is as follows:
A-B + C-D ⟶ A-C + B-D
The bond that breaks and forms during this reaction can be either ionic or covalent bonds. Some examples of this type of reaction include precipitation reactions, acid-base reactions, alkylation, etc.
In the above equation, A and C components of each reactant have switched their places. Generally, these reactions occur in aqueous solutions. Furthermore, we can categorize these reactions as follows;
- Precipitation reactions – A precipitate forms at the end of the reaction. For example, the reaction between silver nitrate and sodium chloride forms silver chloride precipitate and aqueous sodium nitrate.
- Neutralization reactions – An acid neutralizes upon the reaction with a base. For example, an HCl solution (acid) can be neutralized from a NaOH solution (base).
Figure 01: An Example of a Double Displacement Reaction
What is Redox Reaction?
Redox reaction is a type of chemical reaction in which oxidation and reduction half-reactions occur simultaneously. In this reaction, we consider oxidation and reduction as complementary processes. Here, oxidation is the loss of electrons or the increase in the oxidation state while reduction is the gain of electrons or decrease of oxidation state.
Figure 02: Mechanism for Oxidation and Reduction Reactions
Furthermore, the rate of a redox reaction can vary from very slow processes such as rusting to rapid processes such as fuel burning.
What are the Similarities Between Metathesis and Redox Reactions?
- Metathesis and redox reactions are chemical reactions where the products are completely different from reactants.
- Both reactions involve the exchange of something between reactants to give the product(s). e.g exchange of electrons, chemical moieties.
- These reactions involve two complementary reactions. E.g. oxidation-reduction reactions in redox reactions, bond breaking-bond forming reactions in metathesis reactions.
What is the Difference Between Metathesis and Redox Reactions?
Metathesis and redox reactions are two types of chemical reactions. The key difference between metathesis and redox reactions is that in metathesis reactions, the exchange of two ionic species between two molecules occurs whereas, in redox reactions, the exchange of electrons between two chemical species occurs. A double displacement reaction or metathesis is a single-step reaction, but a redox reaction has two parallel half-reactions required for the electron exchange process. Moreover, the oxidation states of atoms necessarily change during a redox reaction but, in metathesis reactions, it may or may not change.
Below infographic summarizes the difference between metathesis and redox reactions.
Summary – Metathesis vs Redox Reactions
Metathesis and redox reactions are two types of chemical reactions. The key difference between metathesis and redox reactions is that in metathesis reactions, the exchange of two ionic species between two molecules occurs whereas, in redox reactions, the exchange of electrons between two chemical species occurs. In addition, metathesis is a single-step reaction, whereas a redox reaction has two parallel half-reactions required for the electron exchange process.
Reference:
1. “Metathesis Reactions.” Chemistry LibreTexts, Libretexts, 5 June 2019, Available here.
2. “Oxidation-Reduction Reactions.” Chemistry LibreTexts, Libretexts, 5 June 2019, Available here.
Image Courtesy:
1. “Aspartate transaminase reaction” By Yikrazuul – Own work (Public Domain) via Commons Wikimedia
2. “Redox Halves” By Cameron Garnham – Own work (CC BY-SA 3.0) via Commons Wikimedia