Worked example: Identifying the best oxidising agent using Eo(red.) values

⁣To identify the best oxidizing agent using Eo(red.) values, you need to compare the Eo(red.) values of the potential oxidizing agents. The species with the higher Eo(red.) value will be the stronger oxidizing agent.

Here are some general rules for comparing Eo(red.) values:

1. The species with the higher Eo(red.) value will be more likely to undergo reduction and, therefore, act as the oxidizing agent.

2. The species with the lower Eo(red.) value will be more likely to undergo oxidation and, therefore, act as the reducing agent.

3. The larger the difference in Eo(red.) values between two species, the stronger the oxidizing agent and the weaker the reducing agent.

For example, consider the following half-reactions:

Half-reaction 1: A+ + e- --> A (Eo(red.) = 0.8 V)
Half-reaction 2: B2+ + 2e- --> 2B+ (Eo(red.) = 1.5 V)

In this case, half-reaction 2 has the higher Eo(red.) value (1.5 V) compared to half-reaction 1 (0.8 V). Therefore, B2+ is the stronger oxidizing agent.

It is important to note that Eo(red.) values can only be compared within the same system, meaning you cannot directly compare Eo(red.) values from different reference electrodes or different systems. Additionally, other factors such as concentration and temperature can also influence the oxidizing strength of a species, so it is important to consider these variables as well.