Why must the number of electrons lost equal the number of electrons gained in every redox reaction?
If the number of electrone gained does not equal the number of electrons lost - then what happens to them? This is why we use the term "balancing"an equation. Everything must be accounted for - nothing is missing.
Thank you !
In a redox reaction, which stands for reduction-oxidation, there is a transfer of electrons between different species. The number of electrons lost by one species must equal the number of electrons gained by another species. This is known as the principle of conservation of charge, or the law of conservation of electrons.
To understand why this principle holds true, we need to consider the overall charge balance in a chemical reaction. In a neutral system, the total charge of reactants should be equal to the total charge of products. Since electrons have a negative charge, their transfer ensures the maintenance of charge neutrality.
So how do we determine the number of electrons transferred in a redox reaction? Here's a step-by-step approach:
1. Assign oxidation numbers: Start by assigning oxidation numbers to all the atoms involved in the reaction. Oxidation numbers are hypothetical charges assigned to individual atoms to track electron transfer. For example, in HCl, the hydrogen atom has an oxidation number of +1, and the chlorine atom has an oxidation number of -1.
2. Identify the species being oxidized and reduced: Determine which species is being oxidized (losing electrons) and which one is being reduced (gaining electrons). The species being oxidized undergoes an increase in oxidation number, while the species being reduced undergoes a decrease in oxidation number.
3. Calculate the change in oxidation numbers: Find the difference in oxidation numbers of the same atom before and after the reaction. This will give you the total number of electrons that are either gained or lost by that atom.
4. Balance the equation: Adjust the coefficients in the balanced equation to ensure that the number of electrons lost by the oxidized species equals the number of electrons gained by the reduced species. This step is crucial for maintaining charge neutrality in the reaction.
By following this approach, you can determine the number of electrons lost and gained in a redox reaction and understand why their quantities must be equal.