EXAMPLE Balancing Redox
Reactions Using the
Oxidation Number Method Balance the following redox equation using either the
inspection technique or the oxidation number method. Be sure to
check that the atoms and the charge are balanced.
NO2(g) + H2(g)
--> NH3(g) + H2O(l)
The atoms in this equation can be balanced by inspection.
(You might first place a 2 in front of the H2O to balance the Os,
then 7/2 in front of the H2 to balance the Hs, and then multiply
all the coefficients by 2 to get rid of the fraction.)
2NO2(g) + 7H2(g)
2NH3(g) + 4H2O(l)
We therefore proceed to Step #2. For the reaction between NO2
and H2, the net charge on both sides of the equation in Step #1 is
zero. Because the charge and the atoms are balanced, the equation is correctly
here to see an exercise that will allow you to try this task yourself.
Return to the Balancing Redox