Oxidation is best defined as
Correct answer: A. loss of electrons and an increase in oxidation number
- A. loss of electrons and an increase in oxidation number
- B. gain of electrons and a decrease in oxidation number
- C. gain of hydrogen only
- D. loss of oxygen only
Explanation
The modern definition is in terms of electrons, so oxidation is loss and reduction is gain, remembered as OIL RIG. Definitions based on adding oxygen or removing hydrogen are older special cases that fail for reactions in which neither element is present. Every oxidation must be accompanied by a reduction, since the electrons lost by one species are gained by another.
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About Oxidation and Reduction
Oxidation involves loss of electrons, increase in oxidation number or addition of oxygen, while reduction involves electron gain, decrease in oxidation number or removal of oxygen. The topic covers oxidising and reducing agents, oxidation-number changes, redox equations and the distinction between oxidation at the anode and reduction at the cathode.
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