Oxidizing Agents

氧化剂

If one reagent in a reaction contributes oxygen, extracts hydrogen, or extracts electrons, it is said to be an oxidizing agent. Of course, it is reduced in the process. Since oxidation and reduction are symmetric processes, always occurring together, there is always an oxidizing agent and a reducing agent in the reaction. Since both are always present, why bother with this terminology?

如果反应中的某一种试剂提供氧、提取氢或提取电子，则称其为氧化剂。当然，在这个过程中它会被还原。由于氧化和还原是相互对称的过程，总是同时发生，因此在任何反应中都必然同时存在氧化剂和还原剂。既然两者总是同时存在，为什么还要用这种术语呢？

If oxidation of some substance is the desired end, then it is useful to find an agent which will readily accomplish the oxidation. Useful oxidizing agents are bleaches and antiseptics. Not so useful is the action of oxygen in the air in the corrosion of metals by oxidation.

如果氧化某种物质是所期望的结果，那么寻找一种能够迅速实现氧化作用的试剂是有用的。有用的氧化剂包括漂白剂和消毒剂。而空气中的氧气在金属氧化生锈过程中的作用则不太有用。

The relative strengths of oxidizing agents can be inferred from their standard electrode potentials. The strongest oxidizing agents are shown from the standard electrode table.

氧化剂的相对强弱可以从标准电极电势推断出来。标准电极表中列出了最强的氧化剂。

Cathode (Reduction) Half-Reaction 阴极（还原）半反应	Standard Potential E^° (volts) 标准电势 E ° (伏特)
MnO₄^-(aq) + 8H⁺(aq) + 5e^- -> Mn²⁺(aq) + 4H₂O(l) MnO₄⁻(aq) + 8H⁺(aq) + 5e⁻ → Mn²⁺(aq) + 4H₂O(l)	1.49
H₂O₂(aq) + 2H⁺(aq) + 2e^- -> 2H₂O(l) H₂O₂（aq）+ 2H⁺（aq）+ 2e⁻ → 2H₂O（l）	1.78
Co³⁺(aq) + e^- -> Co²⁺(aq) Co³⁺(aq) + e⁻ → Co²⁺(aq)	1.82
S₂O₈^2-(aq) + 2e^- -> 2SO₄^2-(aq) S₂O₈²⁻(aq) + 2e⁻ → 2SO₄²⁻(aq)	2.01
O₃(g) + 2H⁺(aq) + 2e^- -> O₂(g) + H₂O(l) O₃（g）+ 2H⁺（aq）+ 2e⁻ → O₂（g）+ H₂O（l）	2.07
F₂(g) + 2e^- -> 2F^-(aq) F₂(g) + 2e⁻ → 2F⁻(aq)	2.87

Fluorine, having the largest positive value of electrode potential, is the strongest oxidizing agent.

氟气具有最大的正电极电势，是最强的氧化剂。

Index

Oxidation/
Reduction concepts

Reference
Hill & Kolb
Ch 8

索引氧化还原概念参考 Hill & Kolb 第8章

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Reducing Agents

还原剂

If one reagent in a reaction removes oxygen, contributes hydrogen, or contributes electrons, it is said to be a reducing agent. Of course, it is oxidized in the process. Since oxidation and reduction are symmetric processes, always occurring together, there is always an oxidizing agent and a reducing agent in the reaction. Since both are always present, why bother with this terminology?

如果反应中的某一种试剂去除氧气、提供氢或提供电子，则称其为还原剂。当然，在这个过程中它会被氧化。由于氧化和还原是相互对称的过程，总是同时发生，因此在任何反应中都必然同时存在氧化剂和还原剂。既然两者总是同时存在，为什么还要使用这种术语呢？

If reduction of some substance is the desired end, then it is useful to find an agent which will readily accomplish the reduction. Hydrogen gas is a very useful reducing agent, used widely in the isolation of pure metals by reduction. For example, copper metal can be obtained by reduction in the reaction

如果某种物质的还原是所期望的结果，那么找到一种能够迅速实现还原的试剂是有用的。氢气是一种非常有用的还原剂，广泛用于通过还原法提纯金属。例如，可以通过以下反应获得铜金属

CuO + H₂ -> Cu + H₂O

The fact that the hydrogen is oxidized in the process is incidental - the hydrogen has performed a very valuable task as a reducing agent.

氢气在该过程中被氧化这一点是次要的——氢气作为还原剂发挥了非常重要的作用。

Important tasks are accomplished by reducing agents as photographic developers and antioxidants. And in photosynthesis, the reducing agents accompish a task which is essential to our survival.

重要的任务由还原剂完成，例如摄影显影剂和抗氧化剂。在光合作用中，还原剂完成了一个对人类生存至关重要的任务。

The relative strengths of reducing agents can be inferred from their standard electrode potentials. The strongest reducing agents are shown from the standard electrode table.

还原剂的相对强弱可以从标准电极电势推断出来。标准电极表中显示了最强的还原剂。

Cathode (Reduction) Half-Reaction 阴极（还原）半反应	Standard Potential E^° (volts) 标准电势 E ° (伏特)
Li⁺(aq) + e^- -> Li(s) Li⁺(aq) + e⁻ → Li(s)	-3.04
K⁺(aq) + e^- -> K(s) K⁺(aq) + e⁻ → K(s)	-2.92
Ca²⁺(aq) + 2e^- -> Ca(s) Ca²⁺(aq) + 2e⁻ → Ca(s)	-2.76
Na⁺(aq) + e^- -> Na(s) Na⁺(aq) + e⁻ → Na(s)	-2.71
Mg²⁺(aq) + 2e^- -> Mg(s) Mg²⁺(aq) + 2e⁻ → Mg(s)	-2.38

Lithium, having the largest negative value of electrode potential, is the strongest reducing agent. By convention, the standard electrode potentials are reduction potentials, or the tendency to be reduced. By that convention, the strongest reducing agents will have large negative potentials.