Identify the role of $\text{H}_2\text{O}_2$(aq) in its reaction with $\text{I}^-$(aq) ions under acidic conditions. Write an ionic equation for the reaction.
A $15.0\,\text{cm}^3$ sample of $\text{C}_6\text{H}_{12}$ is shaken with $20.0\,\text{cm}^3$ of an aqueous $\text{I}_2$ solution until equilibrium is reached. It is found that $0.390\,\text{g}$ of $\text{I}_2$ passes into the $\text{C}_6\text{H}_{12}$. The partition coefficient of $\text{I}_2$ between $\text{C}_6\text{H}_{12}$ and water, $K_{pc}$, is $93.8$. Calculate the mass of $\text{I}_2$ still present in the aqueous layer. Show your working.
Suggest how the value of $K_{pc}$ of $\text{I}_2$ between hexan-2-one, $\text{CH}_3(\text{CH}_2)_3\text{COCH}_3$, and water would compare with the value in (a)(ii). Explain your answer.
Define enthalpy change of solution.
Use the data in Table 1.1 to calculate the enthalpy change of solution for potassium iodide, $\text{KI}$.
Suggest the trend in the magnitudes of the lattice energies of the Group 1 iodides, $\text{LiI}$, $\text{NaI}$, $\text{KI}$. Explain your answer.
A $25.0\,\text{cm}^3$ sample of a $\text{Cu}^{2+}$(aq) solution is reacted with excess $\text{I}^-$(aq). The titration ends when $22.30\,\text{cm}^3$ of $0.150\,\text{mol dm}^{-3}$ $\text{S}_2\text{O}_3^{2-}$(aq) has been added. Calculate the concentration of $\text{Cu}^{2+}$(aq) in the original solution. Reaction 1: $2\text{Cu}^{2+} + 4\text{I}^- \rightarrow 2\text{CuI} + \text{I}_2$ Reaction 2: $2\text{S}_2\text{O}_3^{2-} + \text{I}_2 \rightarrow \text{S}_4\text{O}_6^{2-} + 2\text{I}^-$
Identify a suitable indicator for the titration.
Copper(I) and copper(II) both have electrons in all five $3d$ orbitals. Draw the shape of a $3d_{xy}$ orbital on the axes provided.
The reaction of $\text{I}^-$ ions with persulfate ions, $\text{S}_2\text{O}_8^{2-}$, can be catalysed by $\text{Fe}^{3+}$ ions. $2\text{I}^- + \text{S}_2\text{O}_8^{2-} \rightarrow \text{I}_2 + 2\text{SO}_4^{2-}$ Write equations to show the way in which $\text{Fe}^{3+}$ catalyses this reaction.
An orange precipitate of $\text{HgI}_2$ appears when $\text{Hg}^{2+}$ ions are added to $\text{KI}$(aq). The solubility of $\text{HgI}_2$ at $25\,^{\circ}\text{C}$ is $1.00 \times 10^{-7}\,\text{g dm}^{-3}$.\n\nCalculate the solubility product, $K_{sp}$, of $\text{HgI}_2$.\n\nInclude units in your answer.\n\n$[M_r: \text{HgI}_2, 454.4]$