Chapter 22, Problem 111FP

The decomposition of aqueous hydrogen peroxide is catalyzed by $F{e}^{2t}\left(aq\right)$ . A proposed mechanism for this catalysis involves two reactions. In the first reaction $Fe3+$ is reduced by $E°$ .In the second, the iron is oxidized back to its original form, while hydrogen peroxide is reduced. Write an equation for the overall reaction and show that the overall reaction is indeed spontaneous. What are the minimum and maximum values of $E°$ for a catalyst to function in this way? Which of the following should be able to catalyze the decomposition of hydrogen peroxide by the mechanism outlined here:

a. $C{u}^{2+}$

b. $B{r}^2$

c. $A{l}^{2+}$

d. $A{u}^{2+}?$

In the reaction between iodic acid and hydrogen peroxide in the presence of starch indicator, the color of the reaction mixture oscillates between deep blue and coloriess. What is the basis of these changes in color? Will this oscillation of color continue indefinitely? Explain. [Hint: Refer to Exercise 97 in Chapter 20 , particularly to equation (c).]