Define the term complex.
Table 3.1 contains details of several complexes of $\text{Fe}^{2+}$ and of $\text{Fe}^{3+}$. Complete Table 3.1.
Complete Fig. 3.1 so that it shows the splitting of the d-orbitals in a tetrahedral complex.
Explain why $[\text{Fe(H}_2\text{O)}_6]^{3+}$ and $[\text{Fe(H}_2\text{O)}_5\text{SCN}]^{2+}$ have different colours.
Write an equilibrium expression for $K_{\text{stab}}$ of $[\text{Fe(H}_2\text{O)}_5\text{SCN}]^{2+}$.
Use the data in Table 3.2 to calculate the equilibrium constant, $K_c$, for the reaction below.\n\n$[\text{Fe(H}_2\text{O)}_5\text{SCN}]^{2+} + \text{F}^- \rightleftharpoons [\text{Fe(H}_2\text{O)}_5\text{F}]^{2+} + \text{SCN}^-$
To a solution of $[\text{Fe(H}_2\text{O)}_6]^{3+}\text{(aq)}$, a few drops of $\text{KF(aq)}$ are added and then a few drops of $\text{KSCN(aq)}$. Use the information in Table 3.2 to describe the observations after each addition. Explain your answer.
Write half equations for the oxidation of $\text{C}_2\text{O}_4^{2-}$ ions and the reduction of $\text{MnO}_4^-$ ions.
A student makes up a solution containing $0.100\,\text{g}$ of J. The student titrates the solution with $0.0200\,\text{mol dm}^{-3}$ acidified $\text{KMnO}_4\text{(aq)}$. The titre is $12.20\,\text{cm}^3$. Assume every $\text{C}_2\text{O}_4^{2-}$ ion is oxidised. Calculate the value of $x$ in $\text{K}_3\text{Fe(C}_2\text{O}_4)_3\cdot x\text{H}_2\text{O}$. Give your answer to the nearest whole number. Show your working. $[M_r: \text{K}_3\text{Fe(C}_2\text{O}_4)_3 = 437.1]$