When an excess of the bidentate ligand ethane-1,2-diamine is added to an aqueous solution of nickel(II) sulfate, the green solution turns blue-violet due to the formation of a new complex ion.
Which statement correctly describes this reaction?
It is a redox reaction because the oxidation state of the nickel central metal ion changes.
It is a ligand substitution reaction in which there is a significant increase in entropy (ΔSθ>0\Delta S^\theta > 0ΔSθ>0).
It is a hydrolysis reaction because the amine groups act as bases to deprotonate the coordinated water ligands.
It is a ligand substitution reaction in which the coordination number of the nickel ion decreases from 6 to 3.
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.