___is oxidized in the following reaction: Cr2O7^2- +6S2O3^2- + 14H^+ 2Cr^3+ + 3S4O6^2- + 7H2O

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.