Electrochemical series
A list of standard electrode potentials arranged in increasing or decreasing order, used to predict redox reactions.
What is Electrochemical series?
The potential difference of an electrode measured against the standard hydrogen electrode under standard conditions (298 K, 1 atm, 1 M concentration).
Key formula / rule: Standard Electrode Potential
Key points
- To understand the basis of the electrochemical series.
- To interpret the order of elements in the series.
- To predict the relative strengths of oxidizing and reducing agents.
- To predict the feasibility of redox reactions and displacement reactions.
Common exam trap
Confusing oxidizing and reducing agents based on E° values.
Definitions
- Term
Standard Electrode Potential (E°)
- Meaning
The potential difference of an electrode measured against the standard hydrogen electrode under standard conditions (298 K, 1 atm, 1 M concentration).
- Term
Electrochemical Series
- Meaning
An ordered list of elements based on their standard electrode potentials, indicating their relative tendencies for oxidation and reduction.
- Term
Oxidizing Agent
- Meaning
A substance that tends to gain electrons and cause oxidation in another substance; typically has a high (positive) standard electrode potential.
- Term
Reducing Agent
- Meaning
A substance that tends to lose electrons and cause reduction in another substance; typically has a low (negative) standard electrode potential.
Learning objectives
To understand the basis of the electrochemical series.
To interpret the order of elements in the series.
To predict the relative strengths of oxidizing and reducing agents.
To predict the feasibility of redox reactions and displacement reactions.
Formulae
- Name
Standard Electrode Potential
- Note
Often calculated as E°cell = E°cathode - E°anode, where cathode is where reduction occurs and anode is where oxidation occurs.
- Expression
E° = E°reduction - E°oxidation
- Name
Cell Potential (Standard)
- Note
This formula is used to calculate the standard cell potential of a galvanic cell.
- Expression
E°cell = E°reduction (cathode) - E°reduction (anode)
Prerequisites
Understanding of oxidation and reduction.
Concept of standard electrode potential.
Basic knowledge of ionic compounds and solutions.
Common mistakes
Confusing oxidizing and reducing agents based on E° values.
Incorrectly predicting displacement reactions by not considering the relative positions in the series.
Assuming reactions are spontaneous without checking the overall cell potential (E°cell).
Keywords
Electrochemical Series
Standard Electrode Potential
Redox Reactions
Oxidation
Reduction
Activity Series
Galvanic Cell
Displacement Reaction
Reducing Agent
Oxidizing Agent
Practice preview
Which of the following metals will displace hydrogen from dilute acids?…
easy
According to the electrochemical series, which species is the strongest oxidizing agent?…
easy
Given the standard electrode potentials: E°(Fe$^{3+}$/Fe$^{2+}$) = +0.77 V E°(MnO₄⁻/Mn$^{2+}$) = +1.51 V E°(Cr₂O₇$^{2-}$/Cr$^{3+}$) = +1.33 V E°(Cl₂/Cl⁻) = +1.36 V Which of the following species can oxidize Fe$^{2+}$ ion…
hard