Chemistry 9701 · AS & A Level · Chemistry of transition elements

Chemistry of transition elements — practice question

The reaction scheme illustrates a few reactions involving $[\text{Co}(\text{H}_2\text{O})_6]^{2+}$.
(a(i))[2]

Write the formulae for species A and B.

(a(ii))[1]

State a suitable reagent for reaction 1.

(a(iii))[1]

Write an equation for reaction 2.

(a(iv))[1]

Write an ionic equation for reaction 3.

(b(i))[1]

$\text{Co}^{2+}$ ions catalyse the oxidation of 2,3-dihydroxybutanedioate ions, $\text{C}_4\text{H}_4\text{O}_6^{2-}$, to methanoate ions, $\text{HCO}_2^-$, carbon dioxide and water. What property of transition elements allows $\text{Co}^{2+}$ ions to act as a catalyst?

(b(ii))[1]

Draw the structure of the 2,3-dihydroxybutanedioate ion.

(b(iii))[1]

Complete the equation for the oxidation of 2,3-dihydroxybutanedioate. Use $[O]$ for the oxidising agent in this reaction: $\text{C}_4\text{H}_4\text{O}_6^{2-} + \ldots \rightarrow \ldots$

(c(i))[2]

Draw the structures of these isomers.

(c(ii))[2]

$\textit{Cis}$-platin is an effective anti-cancer drug. Describe the action of $\textit{cis}$-platin in this role.

(d)[1]

Carboplatin may be prepared from $\textit{cis}$-platin, $\text{Pt(NH}_3)_2\text{Cl}_2$, by substituting the two chloride ion ligands with a single cyclobutane-1,1-dicarboxylate ion ligand as shown. Suggest the structure for carboplatin and draw it in the box.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: Species A is $[\mathrm{Co(NH_3)_6}]^{2+}$.

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