# Balancing Redox Reactions: Confusion with Half-Reaction Electron Count

• APHELION
In summary, the conversation revolves around balancing a chemical equation involving Cr(OH)3(s), ClO3−(aq), CrO42−(aq), and Cl−(aq) in a basic solution. The main point of confusion is the half-reaction ClO3− + 6H+ + 6e− ® Cl− + 3H2O, which has a total of 6 electrons instead of 5. It is clarified that both sides of the half-reaction have a charge of -1, and the 6 electrons represent the change in Cl- rather than the total balance charge.
APHELION

## Homework Statement

Cr(OH)3(s) + ClO3−(aq) ® CrO42−(aq) + Cl−(aq) (basic)

I am up the point where I need to balance both half-reactions for electron charge and I'm confused as to why this half reaction: ClO3− + 6H+ + 6e− ® Cl− + 3H2O, has a total of 6 electrons instead of 5. Isn't the overall charge on that side +5, from the difference of 6H+ and 1 ClO3-?

Actually both sides of the half-reaction have charge -1. I looked and it looked balanced to me. If it's balanced, why mess with it?

Really they are both -1? I thought that 6H+ (6e) + ClO- (-1e) = 5 electrons. Wouldn't all the hydrogen atoms carry a 6+ charge on that side? And on the other side, I see why Cl- + 3H20 = -1. H20 carries no charge and Cl- is obviously -1.

ClO- counts as an extra electron, not a deficiency.

What about the 6H+? It doesn't carry a charge?

Actually, I just realized the 6 electrons were not for total balance charge but rather the change in Cl by itself, so the -1 charge does make sense. Thank you!

## 1. What is a redox reaction?

A redox reaction is a chemical reaction in which there is a transfer of electrons between different atoms or molecules. This transfer of electrons results in changes in the oxidation states of the atoms involved.

## 2. How do you determine which element is being oxidized or reduced in a redox reaction?

To determine which element is being oxidized or reduced, you need to identify the initial and final oxidation states of each element involved in the reaction. The element that has a decrease in oxidation state is being reduced, while the element that has an increase in oxidation state is being oxidized.

## 3. What is the purpose of balancing a redox reaction?

The purpose of balancing a redox reaction is to ensure that the number of electrons transferred in the reaction is equal on both sides. This is important because it allows us to accurately calculate the amount of each reactant and product involved in the reaction.

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

To balance a redox reaction, you need to follow a few steps. First, write out the unbalanced equation and identify the elements that are being oxidized and reduced. Then, balance the atoms in the equation by adding coefficients in front of the reactants and products. Finally, balance the charges by adding electrons to the side that is more positively charged.

## 5. What is the difference between a half-reaction and a full redox reaction?

A half-reaction is a representation of either the oxidation or reduction process in a redox reaction, while a full redox reaction is the overall balanced equation for the reaction. Half-reactions are useful in balancing redox reactions because they allow us to focus on one process at a time and determine the amount of electrons being transferred.

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