Cl2 + SO2 + 2 H2O --> 2 Cl^1- + SO4^2- + 4 H^1+
1) Which element is oxidized ? (simply write the element symbol; e.g. Fe, O)
2) How many electrons are lost by each atom ? (1, 2, 3)
3) Which element is reduced ?
4) How many electrons are gained by each atom ?
Oxidation is the loss of electrons. Reduction is the gain of electrons.
You must look at the elements, determine the oxidation state of each, then determine if the element lost or gained electrons.
The secret to all of this is in determining the oxidation state of each element. Here is a site that will show you how to do that. Let me know if there is something you don't understand.
http://www.chemteam.info/Redox/Redox-Rules.html
To determine which element is oxidized and which element is reduced, we need to first identify the oxidation states of the elements in the given chemical equation.
1) Which element is oxidized?
To find the element that is oxidized, we need to compare the oxidation states of the elements on both sides of the equation. In this equation, we have Cl2, SO2, Cl^1-, and SO4^2-.
The oxidation state of Cl in Cl2 is 0. The oxidation state of Cl in Cl^- is -1. Since the oxidation state of Cl decreases from 0 to -1, we can conclude that Cl is oxidized. Therefore, the element that is oxidized is chlorine (Cl).
2) How many electrons are lost by each atom?
To determine the number of electrons lost by each atom, we compare the change in oxidation states of the elements.
In this equation, Cl changes its oxidation state from 0 in Cl2 to -1 in Cl^-. Hence, each Cl atom loses 1 electron.
3) Which element is reduced?
To identify the element that is reduced, we again compare the oxidation states of the elements on both sides of the equation.
The oxidation state of S in SO2 is +4. The oxidation state of S in SO4^2- is +6. Since the oxidation state of S increases from +4 to +6, we can determine that S is reduced. Therefore, the element that is reduced is sulfur (S).
4) How many electrons are gained by each atom?
To determine the number of electrons gained by each atom, we compare the change in oxidation states of the elements.
In this equation, S changes its oxidation state from +4 in SO2 to +6 in SO4^2-. Hence, each S atom gains 2 electrons.
To summarize:
1) The element that is oxidized is chlorine (Cl).
2) Each Cl atom loses 1 electron.
3) The element that is reduced is sulfur (S).
4) Each S atom gains 2 electrons.