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

Chemistry of transition elements — practice question

Maleic anhydride is an unsaturated cyclic compound that is used to make several polymers. It can be converted into maleic acid and tartaric acid, as shown in Fig. 6.1.
(a(i))[2]

Maleic acid reacts with ethane-1,2-diol to produce a condensation polymer. Draw part of this polymer, showing only one repeat unit. The newly formed functional group must be displayed in full.

(a(ii))[1]

Identify a suitable reagent and the conditions for reaction 2.

(b(i))[1]

Suggest the type of reaction that occurs in step 1.

(b(ii))[2]

U can act as a bidentate ligand. Explain what is meant by a bidentate ligand.

(b(iii))[2]

Complete the three-dimensional diagrams in Fig. 6.3 to show both stereoisomers of $[\text{Cu(U)}_3]^{4-}$. Use the symbol shown to represent ligand U.

(c(i))[1]

Identify the number of different carbon environments present in X.

(c(ii))[1]

Explain why X is dissolved in $\text{D}_2\text{O}$ before obtaining its proton ($^1\text{H}$) NMR spectrum.

(c(iii))[4]

Aromatic compound X forms a yellow precipitate when it reacts with alkaline $\text{I}_2(\text{aq})$. Using the information in part (c), suggest a structure for X, $\text{C}_8\text{H}_8\text{O}_3$. Explain your reasoning.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: Ester linkage correctly placed between the two monomers

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