Therefore, the following answer does not need to introduce Na element, and can be replaced by M.

Na2O2 + C === 2Na + CO2

Na2O2 + 2C === 2Na + 2CO

Na2O2 + 2CO ==== 2Na + 2CO2

Carbon dioxide+carbon dioxide = = carbon dioxide

Of course, it is also possible to use knowledge outside of middle school to solve problems. It should be PbO, light yellow. It also meets the requirements of inference.