Basic concept doubts in redox reactions

Click For Summary

Discussion Overview

The discussion revolves around understanding redox reactions, specifically determining whether a given reaction involving oxalate ion ([C2O4]-2) is an oxidation or reduction process, and calculating the number of electrons lost or gained by carbon during the reaction. The scope includes homework-related questions and conceptual clarifications regarding oxidation states and electron transfer.

Discussion Character

  • Homework-related
  • Conceptual clarification
  • Mathematical reasoning

Main Points Raised

  • The initial poster expresses confusion about the oxidation states of carbon and oxygen in the reaction and attempts to interpret the changes in oxidation state to determine electron transfer.
  • Some participants suggest that using half-reactions might simplify the process of understanding electron transfer compared to relying solely on oxidation numbers.
  • The initial poster revises their calculations and reasoning, concluding that if the oxidation state of carbon increases from 3+ to 4+, it implies that an electron has been removed, leading to further calculations regarding the total number of electrons involved.
  • A later reply confirms that electrons are indeed removed in the reaction, indicating a loss of electrons from carbon.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the interpretation of oxidation states and the number of electrons involved, as the initial poster's understanding evolves throughout the discussion. Some participants propose alternative methods for analysis, indicating differing approaches to the problem.

Contextual Notes

The discussion includes varying interpretations of oxidation states and electron transfer, with some participants suggesting that the approach using half-reactions may provide clearer insights. There is also an acknowledgment of the complexity involved in balancing the reaction and determining the correct number of electrons lost or gained.

Who May Find This Useful

Students and individuals seeking to understand redox reactions, oxidation states, and electron transfer processes in chemistry may find this discussion beneficial.

takando12
Messages
122
Reaction score
5

Homework Statement


[C2O4]-2 ------> CO2
Find if the reaction is oxidation or reduction and determine the no. of electrons lost or gained by carbon.

Homework Equations

The Attempt at a Solution


I started with finding the oxidation states of both elements. It's 3+ and 2- for carbon and oxygen on the LHS and 4+ and 2- for carbon and oxygen on the RHS. But i am having trouble in interpreting these values.
the OS of carbon goes from 3+ to 4+. My interpretation of this was that C had lost 3 electrons on the LHS while lost 4 electrons on the RHS to O. Hence I thought that C should have gained 1 electron. And this means it's reduction and that's the wrong answer. Can someone please correct my interpretation and help me out with this? This is quite a silly and basic question. Please bear with me, I am new to this.
 
Physics news on Phys.org
takando12 said:
C had lost 3 electrons on the LHS while lost 4 electrons on the RHS to O. Hence I thought that C should have gained 1 electron.

Think it over.

But in general, this is much easier done without oxidation numbers, just using half reactions. It is trivial to balance atoms, then it is trivial to see where the electrons have to be added (on which side) to balance the charge.
 
Borek said:
Think it over.

But in general, this is much easier done without oxidation numbers, just using half reactions. It is trivial to balance atoms, then it is trivial to see where the electrons have to be added (on which side) to balance the charge.
Ok I tried again. The OS of C on LHS is 3+ meaning there are 3 more protons than electrons. This goes to a 4+ on the RHS , 4 more protons than electrons , which means 1 electron must have been removed. And balancing the reaction we get 2CO2 on the LHS. So multiplying the OS with the no of atoms., i got 6+ on the LHS and 8+ on the RHS. Hence applying the same logic, 2 electrons must have been removed? Is this right?
 
Yes, electrons are removed.

C2O42- → 2CO2 + 2e-
 

Similar threads

Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 7 ·
Replies
7
Views
10K