Peroxodisulfate S2O8 2- reacts with thiosulfate (S2O3 2-) according to the following reaction (S{2}O{8} {2-} + 2S{2}O{3} {2-} -->2SO{4} {2-} + S{4}O{6} {2-})
a) Illustrate how the change in peroxodisulfate with time is related to the change in concentration with time of the other three species.
b) Explain if the reaction is elementary and irreversible define what is the overall order of the reaction.