posted by TARA .
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.