# Basic concept doubts in redox reactions

• takando12
In summary, the reaction of [C2O4]-2 to CO2 involves a reduction, with carbon losing two electrons in the process. This can be determined by balancing the atoms and charges, rather than using oxidation numbers.
takando12

## Homework Statement

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

## 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.

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-

## 1. What is a redox reaction?

A redox reaction is a chemical reaction in which one or more atoms undergo a change in their oxidation states. This change is accompanied by a transfer of electrons between reactants, resulting in the formation of new compounds.

## 2. How do you determine the oxidation state of an atom?

The oxidation state of an atom can be determined by following a set of rules. First, the oxidation state of a free element is always 0. Second, the oxidation state of a monatomic ion is equal to its charge. Third, the sum of the oxidation states of all atoms in a neutral molecule must be 0, and in an ion it must be equal to the charge of the ion. Finally, in most cases, oxygen has an oxidation state of -2 and hydrogen has an oxidation state of +1.

## 3. What is the difference between oxidation and reduction?

Oxidation and reduction are two opposite processes that occur simultaneously in a redox reaction. Oxidation is the process in which an atom loses electrons, while reduction is the process in which an atom gains electrons. An easy way to remember this is through the acronym "OIL RIG" - oxidation is loss, reduction is gain.

## 4. How do you balance a redox equation?

In order to balance a redox equation, you must first assign oxidation numbers to each atom in the reactants and products. Then, use the rules for balancing redox reactions which state that the number of electrons lost during oxidation must equal the number of electrons gained during reduction. You may also need to add coefficients to balance the number of atoms on each side of the equation.

## 5. What are some examples of redox reactions?

Some common examples of redox reactions include combustion (such as burning wood or gasoline), corrosion (the rusting of iron), and photosynthesis (the process by which plants convert sunlight into energy). Other examples include the reactions involved in battery cells and the metabolism of food in our bodies.

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