1. The problem statement, all variables and given/known data Hi. I have convert the following equation (which is in ionic form) into neutral form: 4S2O32-+O2+2H2O=2S4O62-+4OH- The question tells me to use calcium as a counterion for all anions. 2. Relevant equations N/A 3. The attempt at a solution I basically just added calcium to the anions above, resulting in: 4CaS2O3+O2+2H2O=2CaS4O6+4Ca(OH)2 Unfortunately, when I do a check, the coefficients of each element/compound do not match. Trying to balance it doesn't work.