How do we represent the oxidation of thiosulfate anion, #S_2O_3^(2-)# to tetrathionite, #S_4O_6^(2-)#...?

1 Answer
May 27, 2017

Answer:

#"Thiosulfate to tetrathionite..........."#

#2S_2O_3^(2-) rarr S_4O_6^(2-)+2e^(-)# #;stackrel(II)Srarrstackrel(II*1/2)S#

Explanation:

I always considered #"thiosulfate dianion"#, #S_2O_3^(2-)#, to be the same as sulfate dianion, #SO_4^(2-)#, EXCEPT that one of the oxygen atoms has been replaced by congeneric sulfur. And this sulfur has PRECISELY the same oxidation state as the oxygen it replaces, i.e. #stackrel(-II)S#. The AVERAGE oxidation states is still.................................

#(S(-II)+S(+VI))/2=S(+II)#

Anyway, let's try to balance the beast.

#2S_2O_3^(2-) rarr stackrel()S_4O_6^(2-)+2e^(-)# #;stackrel(II)Srarrstackrel(II*1/2)S#

Do you agree that it is balanced with respect to mass and charge?