Hydrogen peroxide and the iodide ion react in acidic solution as follows:
$$\mathrm{H}_{2} \mathrm{O}_{2}(a q)+3 \mathrm{I}^{-}(a q)+2 \mathrm{H}^{+}(a
q) \longrightarrow \mathrm{I}_{3}^{-}(a q)+2 \mathrm{H}_{2} \mathrm{O}(l)$$
The kinetics of this reaction were studied by following the decay of the
concentration of \(\mathrm{H}_{2} \mathrm{O}_{2}\) and constructing plots of
\(\ln \left[\mathrm{H}_{2} \mathrm{O}_{2}\right]\) versus time. All the plots
were linear and all solutions had \(\left[\mathrm{H}_{2}
\mathrm{O}_{2}\right]_{0}=8.0 \times 10^{-4} \mathrm{mol} / \mathrm{L} .\) The
slopes of these straight lines depended on the initial concentrations of
\(\mathrm{I}^{-}\) and
\(\mathrm{H}^{+} .\) The results follow: The rate law for this reaction has the
form $$\text { Rate }=\frac{-\Delta\left[\mathrm{H}_{2}
\mathrm{O}_{2}\right]}{\Delta
t}=\left(k_{1}+k_{2}\left[\mathrm{H}^{+}\right]\right)\left[\mathrm{I}^{-}\right]^{m}\left[\mathrm{H}_{2}
\mathrm{O}_{2}\right]^{n}$$ a. Specify the order of this reaction with respect
to \(\left[\mathrm{H}_{2} \mathrm{O}_{2}\right]\) and
\(\left[\mathrm{I}^{-}\right]\)
b. Calculate the values of the rate constants, \(k_{1}\) and \(k_{2}\)
c. What reason could there be for the two-term dependence of the rate on
\(\left[\mathrm{H}^{+}\right] ?\)