Chemistry / Unit 3 Chem 0459 short lesson, about 20 seconds
Oxidation-Reduction (Redox) Reactions
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The idea
A redox reaction is one where at least one element's oxidation number rises while another's falls, tracking an electron transfer.
In practice
When sodium reacts with chlorine, sodium's oxidation number rises from 0 to +1 while chlorine's falls from 0 to −1.
Where people slip
A reaction with no oxidation-number change, such as most precipitation or acid-base reactions, is not a redox reaction at all.
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