Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: ygao85 on June 13, 2005, 10:21:16 PM
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When we are given a bunch of reaction how do we know which one is a redox reaction? Is there any trick that can tell you right away that a reaction is a redox rxn.
Also why is this eqn not a redox rxn:
Cr2O72-(aq)+2OH-(aq)-->2CrO42-(aq)+H2O(l).
Thank you.
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one quick way to determine is see if there is any change in valency /oxidation number in anyone of the reactants.
your eqn is not redox becos Cr2O7 2- has chromium in 6+ oxidation state, but CrO4 2- also has chromium in 6+ oxidation state.
same goes for hydroxide. oxygen and hydrogen have no changes in valency/oxidation state.