Question

Fluorine is best oxidising agent because (a) it is most electronegative. (b) it has highest reduction potential. (c) it has highest oxidation potential. (d) it has smallest size.

Short answer

Fluorine is the best oxidizing agent because it has the highest reduction potential.

Step-by-step solution

Understanding Oxidizing Agents

An oxidizing agent is a substance that has the ability to oxidize other substances by gaining electrons itself. In a redox (reduction-oxidation) reaction, the oxidizing agent gets reduced. The strength of an oxidizing agent is determined by its ability to accept electrons, which can be influenced by factors such as electronegativity, reduction potential, oxidation potential, and atomic size.

Analyzing Electronegativity

Electronegativity is the ability of an atom to attract shared electrons in a chemical bond. While fluorine is the most electronegative element, this does not directly explain its property as an oxidizing agent. Rather, high electronegativity suggests that the atom is very good at attracting electrons when it forms bonds, which is related but not the sole reason for being a good oxidizing agent.

Examining Reduction Potential

The reduction potential is a measure of the tendency of a chemical species to acquire electrons and thereby be reduced. Fluorine has the highest reduction potential among all elements, meaning it has a very strong tendency to gain electrons and undergo reduction. This is a direct indicator of its ability to act as an oxidizing agent.

Considering Oxidation Potential

Oxidation potential is the opposite of reduction potential and indicates the tendency to lose electrons. However, in the context of oxidizing agents, it is the reduction potential that is significant because the oxidizing agent itself is reduced during the reaction. Therefore, a high reduction potential, not oxidation potential, makes for a strong oxidizing agent.

Looking at Atomic Size

A smaller size may mean that the nucleus can more effectively attract electrons when forming a bond, but this factor alone is not the primary reason for an element's oxidizing strength. The effect of size is already incorporated into the other properties like electronegativity and reduction potential.

Determining the Correct Answer

From the given options and explanations, we can determine that the primary reason for fluorine's strength as an oxidizing agent is its highest reduction potential. Therefore, option (b) is the correct answer.

Key concepts

Electronegativity

Electronegativity is a fundamental concept in chemistry that describes the tendency of an atom to attract a shared pair of electrons towards itself when it forms a chemical bond. The electronegativity scale was developed by Linus Pauling, and it ranges from 0 to 4. Fluorine, with an electronegativity of 3.98, is the most electronegative element on the periodic table.

This high electronegativity implies that fluorine has a strong pull on electrons, which is crucial when it comes to forming bonds with other elements. While an atom's electronegativity doesn't directly determine its ability to function as an oxidizing agent, it's a contributing factor since an atom with higher electronegativity will more readily attract electrons from other substances. As a result, these other substances get oxidized. However, it's important to remember that although fluorine's high electronegativity sets the stage for its oxidizing capabilities, it's the reduction potential that cinches its role as an excellent oxidizing agent.

Reduction Potential

Reduction potential, often represented as E0 (standard electrode potential), is a quantitative measure of a substance's ability to gain electrons and thus be reduced. In redox reactions, the direction and extent to which a reaction proceeds can be predicted by comparing the reduction potentials of the reactants. A higher reduction potential indicates a greater likelihood of the species to accept electrons and undergo reduction.

In the case of fluorine, it has the highest reduction potential among all the elements, a whopping +2.87 volts. This high value implies that fluorine is extremely eager to gain electrons, making it a very powerful oxidizing agent. It's this ability to act as an electron sink that underlies fluorine's status as the top oxidizing agent in the periodic table. When considering oxidizing abilities, reduction potential offers a more direct insight than does electronegativity, which is more about electron-sharing than electron-gaining, which is the hallmark of reduction.

Fluorine as an Oxidizing Agent

Fluorine's reputation as the best oxidizing agent in chemistry is due to a combination of factors, with its extraordinary reduction potential taking center stage. As an oxidizing agent, fluorine's job in a chemical reaction is to accept electrons from other substances, thereby causing those substances to be oxidized while it itself gets reduced.

The strength of fluorine as an oxidizing agent is unparalleled because when it comes to gaining electrons, fluorine is essentially the most 'electron-hungry' element. This can be attributed to its small atomic size, which allows its nucleus to exert a strong pull on nearby electrons, and its electronegativity, which underlies its ability to attract electrons from other atoms.

However, while its electronegativity and atomic size contribute to its overall chemical behavior, it's truly fluorine's reduction potential that pinpoints its oxidizing prowess. This potential drives the energetics of redox reactions, favoring fluorine's reduction and leading to the oxidation of the opposing reactant. Simply put, when fluorine is part of a reaction, its powerful drive to gain electrons (high reduction potential) supersedes other factors, ensuring that it consistently acts as a superior oxidizing agent.