and the hydrogens by adding hydrogen ions:
Now all that needs balancing is the charges. Add 6 electrons to the left-hand side to give a net 6+ on each side.
Combining the half-reactions to make the ionic equation for the reaction
What we have so far is:
What are the multiplying factors for the equations this time? The simplest way of working this out is to find the smallest number of electrons which both 4 and 6 will divide into - in this case, 12. That means that you can multiply one equation by 3 and the other by 2.