Order of Reactions occurring in aqueous solutions

[neilparker62]

A well known rate of reaction experiment is the reaction between sodium thiosulphate and Hydrochloric acid in which colloidal Sulphur is produced. Over time this obscures a cross placed beneath the reaction vessel. Reaction time can then be measured for various concentrations of thiosulphate.

Plotting 1/t against concentration yields a (more or less) straight line graph and my question is what order of reaction is this ? And how does one derive it ? More generally, how is rate of reaction determined for any particular reaction occurring in aqueous solution ? There are a lot of internet videos showing the thiosulphate practical but none seem to discuss in any depth the theoretical reaction kinetics.

 

[Lord Jestocost]

John E. Straub’s lecture notes (Boston University, Chemistry/Computational Science) might be of help: “Experimental determination of the orders of reaction by varying concentration”: https://people.bu.edu/straub/courses/demomaster/colloidalsulfur.html