Final answer:
In the given reaction, sulfur undergoes disproportionation. To address the reaction, balance the equation by ensuring that both sides have an equal number of atoms for each element.
Step-by-step explanation:
In the given reaction, S2O3(-2) (aq) + 2H+ (aq) → S (s) + SO2 (g) + H2O (l), the element that undergoes disproportionation is sulfur (S). Disproportionation is a redox reaction where the same element is both oxidized and reduced.
In this reaction, sulfur is simultaneously oxidized from an oxidation state of -2 to 0 and reduced from -2 to 0. The S2O3(-2) ion is reduced to S (solid) and also oxidized to SO2 (gas).
To address this reaction, you should balance the equation by ensuring that both sides of the equation have an equal number of atoms for each element.