Explain why transition elements behave as catalysts.
State the oxidation state and the coordination number of titanium in $[\text{TiCl}_4(\text{diars})_2]$, where diars is a neutral bidentate ligand.
Use three-dimensional drawings to show the shapes of $[\text{Ag(CN)}_2]^- $ and $[\text{Cu(CN)}_4]^{3-}$ in the boxes. Mark one bond angle on each diagram.
Write an expression for the stability constant, $K_{\text{stab}}$, of $[\text{Cu(CN)}_4]^{3-}$.
In a solution, the concentrations of $\text{CN}^-$ and $[\text{Cu(CN)}_4]^{3-}$ are each $0.0010\,\text{mol dm}^{-3}$. Use your expression from (c)(i) together with the value of $K_{\text{stab}}$ to calculate the concentration of $\text{Cu}^+(\text{aq})$ in this solution.
Calculate the number of moles of $\text{I}_2$ that are reduced in this titration.
Calculate the number of moles of copper in the original piece of alloy.
Calculate the percentage of copper in the alloy.
Suggest why a solution of $\text{Cu}^{2+}$ is coloured but solid $\text{CuI}$ is white.