12i-+Na2O2+2h2o = I2+2na+4oh-,the reductant of this reaction is i-, the oxidant is sodium peroxide, the reduction product is I2, and the oxidation product is na+. Among them, I2 is a weak oxidant, and the corresponding I- has strong reducibility; As a kind of peroxide, sodium peroxide has strong oxidation. Sex, accordingly, has hardly decreased. Therefore, the reaction is between strong reducing agent I- and strong oxidant Na2O2, weak oxidation product I2 and weak reducing agent OH-.

2 2NaS+O2+2CO2=2NaCO3+2S precipitation; The reducing agent is divalent sulfur ion, which is oxidized to generate sulfur element precipitation; As an oxidant, O2 is reduced to O2- to generate Na2O, which reacts with carbon dioxide to generate sodium carbonate.

Answer your question here, why there are so many valence states of iodine, and why it must be iodine?

Chemical reactions need certain reaction conditions, and the conclusions obtained by changing the conditions are different.

Just like the above reflection, whether the reactants are excessive or not will also affect the results. The above reaction occurs under normal conditions, and changing the conditions will often produce unexpected results. In fact, this solution involves four main equilibria. After studying college chemistry, you will have a deeper understanding.