Question

How do we speed up the disproportionation reaction of `"thiosulfate ion"` to give elemental sulfur, and sulfate anion?

Answer 1

The two ways to speed up sulfur disproportionation are (i) raise the temperature, or (ii) add a catalyst. Changing the concentration of reactants will also cause the speed of the reaction to change.

Explanation:

As you know, sulfur in thiosulfate will disproportionate under these conditions. The reaction is distinguished by the deposit of a fine white precipitate of elemental sulfur.

`S_2O_3^(2-) + 2HCl(aq) rarr S(s) + SO_2(g) + 2Cl^(-)(aq) +H_2O(l)`

Any reaction rate will reasonably increase upon the increase of temperature. A reaction rate will also increase upon the addition of a catalyst. A solid metal surface (of silver?) should act as a heterogeneous catalyst.

Another way of changing the speed of a reaction like this is to change the concentration of reactants. Here is a video showing this effect...