CoCl2 + Na2O2 → Co(OH)3 + Cl- + Na+
Step 1. Separate the whole reaction into half-reactions
CoCl2 → Co(OH)3 + Cl- Na2O2 → Na+
Step 2. Balance the non-hydrogen and non-oxygen elements first
CoCl2 → Co(OH)3 + 2 Cl- Na2O2 → 2 Na+
Balance the following equation in basic conditions. Phases are optional.
CoCl2+Na2O2 = Co(OH)3+Cl- +Na+
(redox and oxidation reactions)