In a clock reaction 20.0mL of 0.200M KI, 20.0mL of 0.100M (NH4)2S2O8 and 10.0mL of 0.00500M Na2S2O3 were mixed in the presence of a starch solution indicator. The solution turned blue in 63.9 seconds.
a. Explain what were the initial molar concentrations of (I)- , (S2O8)2- and (S2O3)2- in the reaction mixture?
b. Explain what percent of the (S2O8)2- has reacted when the mixture turned blue?