Chemistry Question

[shaiga95]

The molarity of an iodine solution may be determined
by reacting it with a thiosulfate solution. In
this procedure I2 is reduced to I
ions, while the
S2O3 2-
ions are oxidised to S4O6 2-
ions.
An iodine solution which is known to be about
0.02 mol L
1 is to be standardised. A certain mass
of sodium thiosulfate is to be weighed out, and
then made up to 250 mL. This solution will then be
titrated against a 20 mL sample of the iodine. The
average titre should be approximately 20 mL for this
procedure.
Calculate the mass of sodium thiosulfate
required.

[teletubbies_95]

Hi .
I think I worked it out But yeh , check with the more experienced
Hope it helps

[shaiga95]

How did you get your equation I got I2 +2S2O3 2- -> 2I- + S4O6 2-
with half equations I2 +2e- -> 2I-
2S2O3 2-   ->  S4O6 2- + 2e-

[teletubbies_95]

sos your right. i just confused myself.
SORRY . im so dumb at times .

[teletubbies_95]

sos for the wrong moles ,etc. just use the same steps. you'll get the answer.

GOOD LUCK ! Hope that helped !

[shaiga95]

Thanks for your help