Using the qualitative model of electron-pair repulsion, explain why the IO$_3^-$ anion is pyramidal in shape.
The reaction of iodine with hot aqueous sodium hydroxide is analogous to that of chlorine with hot aqueous sodium hydroxide. One of the products is sodium iodate, NaIO$_3$. Suggest an equation for the reaction of iodine with hot aqueous sodium hydroxide.
Use the data to demonstrate that the two separate reactions of H$_2$O$_2$ with IO$_3^-$ and with I$_2$ are both feasible under standard conditions. In your answer, include the equation for the reaction of H$_2$O$_2$ with I$_2$.
Write the overall equation for the decomposition of H$_2$O$_2$ catalysed by acidified IO$_3^-$.
Use the data to determine the order of reaction with respect to H$_2$O$_2$, IO$_3^-$ and H$^+$. Show how you reached your answer.
Use your answer to d(i) to write the rate equation for this reaction.
Calculate the value of the rate constant, $k$, using the data from experiment 4 and your answer to d(ii). Give the units of $k$.
$\text{Pb(IO}_3)_2$ is only sparingly soluble in water at $25^\circ\text{C}$. The solubility product, $K_{sp}$, of $\text{Pb(IO}_3)_2$ is $3.69 \times 10^{-13}\ \text{mol}^3\text{dm}^{-9}$ at $25^\circ\text{C}$. Write an expression for the solubility product of $\text{Pb(IO}_3)_2$.
Calculate the solubility, in $\text{mol dm}^{-3}$, of $\text{Pb(IO}_3)_2$ at $25^\circ\text{C}$.
$\text{NH}_4\text{IO}_3(s)$ is an unstable compound that decomposes readily on heating. The decomposition reaction is shown. $\text{NH}_4\text{IO}_3(s) \rightarrow \tfrac{1}{2}\text{N}_2(g) + \tfrac{1}{2}\text{O}_2(g) + \tfrac{1}{2}\text{I}_2(g) + 2\text{H}_2\text{O}(l) \qquad \Delta H = -154.6\ \text{kJ mol}^{-1}$ Use the information in the table to calculate the entropy change of reaction, $\Delta S$, for the decomposition of $\text{NH}_4\text{IO}_3(s)$.
This reaction is feasible at all temperatures. Explain why, using the data in f and your answer to f(i).