Which statement regarding the ligand substitution reactions of copper(II) complexes is not correct?
Addition of an excess of concentrated hydrochloric acid to [Cu(H2O)6]2+(aq)[\text{Cu}(\text{H}_2\text{O})_6]^{2+}(\text{aq})[Cu(H2O)6]2+(aq) results in a change in coordination number from 6 to 4 and a change in shape from octahedral to tetrahedral.
The substitution of monodentate water ligands in [Cu(H2O)6]2+[\text{Cu}(\text{H}_2\text{O})_6]^{2+}[Cu(H2O)6]2+ by bidentate 1,2-diaminoethane ligands is thermodynamically favored due to a significant positive entropy change (ΔS∘>0\Delta S^\circ > 0ΔS∘>0).
The addition of excess aqueous ammonia to [Cu(H2O)6]2+(aq)[\text{Cu}(\text{H}_2\text{O})_6]^{2+}(\text{aq})[Cu(H2O)6]2+(aq) results in complete substitution of all six water ligands to form the octahedral complex [Cu(NH3)6]2+[\text{Cu}(\text{NH}_3)_6]^{2+}[Cu(NH3)6]2+.
The substitution of water ligands in [Cu(H2O)6]2+[\text{Cu}(\text{H}_2\text{O})_6]^{2+}[Cu(H2O)6]2+ by three bidentate ethanedioate (C2O42−\text{C}_2\text{O}_4^{2-}C2O42−) ligands forms a complex that exhibits optical isomerism.
63 exam-style questions on AQA A Level Chemistry Transition metals (A-level only), covering General properties of transition metals (A-level only), Substitution reactions (A-level only), Shapes of complex ions (A-level only), Formation of coloured ions (A-level only), Variable oxidation states (A-level only), and Catalysts (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.