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Question
Consider the reaction
`3I_((aq))^-) +S_2O_8^(2-)->I_(3(aq))^-) + 2S_2O_4^(2-)`
At particular time t, `(d[SO_4^(2-)])/dt=2.2xx10^(-2)"M/s"`
What are the values of the following at the same time?
a. `-(d[I^-])/dt`
b. `-(d[S_2O_8^(2-)])/dt`
c. `-(d[I_3^-])/dt`
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Solution
Rate of reaction
`-(1/3)(d[I^-])/dt = -(d[S_2O_8^-2])/dt = +(d[I_3^-])/dt = +(1/2)(d[SO_4^-2])/dt`
`(d[SO_4^-2])/dt=2.2xx10^-2 "M/s"`
(a)
`-(1/3)(d[I^-])/dt = (1/2)(d[SO_4^-2])/dt`
`-(d[I^-])/dt=3/2xx2.2xx10^-2`
`-(d[I^-])/dt=3.3xx10^-2 " M/s"`
(b)
`-(d[S_2O_s^(-2)])/dt=(1/2)(d[SO_4^-2])/dt`
`-(d[S_2O_s^(-2)])/dt=1/2xx2.2xx10^-2`
`-(d[S_2O_s^(-2)])/dt=1.1xx10^-2 " M/s"`
(c)
`(d[I_3^-])/dt=(1/2)(d[SO_4^-2])/dt`
`(d[I_3^-])/dt=1/2xx2.2xx10^-2`
`(d[I_3^-])/dt=1.1xx10^-2`
`-(d[I_3^-])/dt=-1.1xx10^-2 " M/s"`
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