Oxidation and reduction problems

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Discussion Overview

The discussion revolves around the concepts of oxidation and reduction, particularly in the context of chemical reactions. Participants explore definitions, examples, and the nuances of these processes, questioning the sufficiency of traditional definitions and seeking clarity on specific reactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions whether the definition of oxidation as gaining oxygen is too vague, suggesting that gaining or losing other species may complicate the classification of a reaction as oxidation or reduction.
  • Another participant asserts that oxidation is defined as losing electrons and reduction as gaining electrons, seeking to clarify this point in relation to a specific reaction involving Cr2O7 2-.
  • A participant proposes that Cr2O7 2- gains electrons in the reduction process, referencing the base equation of oxidant and electron(s) leading to a product.
  • Another participant presents a simplified view of the reduction process using the equation Cr6+ + 3e- -> Cr3+, indicating a potential method of explanation.
  • There is a query about whether it is valid to explain reduction in terms of losing oxygen, indicating a search for alternative explanations beyond electron transfer.

Areas of Agreement / Disagreement

Participants express differing views on the definitions and explanations of oxidation and reduction, with no consensus reached on the sufficiency of traditional definitions or the best way to explain specific reactions.

Contextual Notes

Participants highlight limitations in using traditional definitions, such as the role of species other than oxygen and the complexity of certain reactions, indicating a need for more nuanced explanations.

Who May Find This Useful

This discussion may be of interest to students and educators in chemistry, particularly those exploring redox reactions and seeking deeper understanding of oxidation and reduction concepts.

sgstudent
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When something is oxidized, it gains oxygen, loses hydrogen or loses electron. However, if the substance gains something else other than oxygen then it won't be considered oxidation anymore? For instance H+ +OH- -->H2O so in this case it seems that the H+ gained oxygen from OH- but actually the H+ ion was not oxidized as the full reaction is HCl+NaOH-->H2O+NaCl so the compound containing the hydrogen ion aka HCl lost the chlorine and gains oxygen so it was not oxidized?

So is saying a compound gains oxygen too vague? Because if the substance loses and gains something else other than oxygen then the substance might not be oxidized at all? I think it would apply for the gain or lost in hydrogen as well. Because it appears that the hydroxide ion gained another hydrogen, however it was not reduced.

That being said when Cr2O7 2- +14H+ +6e-->2Cr3+ +7H2O, how are we going to explain how it became reduced?

We can't use the gain of hydrogen as Cr3+ does not contain any hydrogen and can't use the lost in oxygen as besides losing oxygen it lost a cation in Cr2O7 2- and gained an anion in Cr3+. So how should I explain its reduction without using oxidation states?

Thanks for the help :)
 
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Oxidation is loosing electrons, reduction is gaining them.
 
Alkim said:
Oxidation is loosing electrons, reduction is gaining them.

Oh but can i say the Cr2O7 2- gains electrons? Since the actual base equation given is oxidant+electron(s) ->product.

Thanks for the help :)
 
Another way of seeing it is: Cr6+ + 3e- -> Cr3+
 
Alkim said:
Another way of seeing it is: Cr6+ + 3e- -> Cr3+

Hi thanks for the reply :smile:

Oh I didn't know I could do that. But in this case is it possible for me to explain it by losing oxygen?
 

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