How do you balance redox equations using the oxidation number change method?
#ClO_3^(-) (aq) + I^(-) (aq) -> Cl^(-) (aq) + I_2 (aq)# [acidic solution
You introduce electrons as virtual particles and assign oxidation states...according to given rules.
Chlorate is REDUCED to chloride....
Iodide is oxidized to iodine...
In each case we account for the difference in oxidation number by the addition (reduction) or subtraction (oxidation) of electrons....
....to give finally after cancellation...
The which is balanced with respect to mass and charge....as indeed it must be if we purport to represent chemical reality....
WARNING! Long answer! The balanced equation is
The unbalanced equation is
Step 1. Identify the atoms that change oxidation number
Start by determining the oxidation numbers of every atom in the equation.
We see that the oxidation number of
The changes in oxidation number are:
Step 2. Equalize the changes in oxidation number
We need 6 atoms of
Step 3. Insert coefficients to get these numbers
Step 4. Balance
Step 5. Balance
Every formula now has a coefficient. The equation should be balanced.
Step 6. Check that all atoms are balanced.
Step 7. Check that charge is balanced.
The balanced equation is