OCR A Jun 2013 Paper 5 Q5

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Iron is heated with chlorine to form an orangebrown solid, A. 12 Solid A is dissolved in water to form an orangebrown solution, X, containing the complex ion [Fe(H2O)6]3+. Separate portions of solution X are reacted as shown in Experiments 14 below. Experiment 1 Aqueous sodium hydroxide is added to solution X. An orangebrown precipitate B forms. Experiment 2 Excess zinc powder is added to solution X and the mixture is heated. The excess zinc is removed leaving a pale-green solution containing the complex ion C and aqueous Zn2+ ions. Experiment 3 An excess of aqueous potassium cyanide, KCN(aq), is added to solution X. The solution turns a yellow colour and contains the complex ion E. E has a molar mass of 211.8 g mol1. Experiment 4 An aqueous solution containing ethanedioate ions, (COO)2, is added to solution X. A coloured solution forms containing a mixture of optical isomers F and G. The structure of the ethanedioate ion is shown below. O O (a) Write an equation for the formation of solid A.[1] (b) In Experiment 1, write an ionic equation for the formation of precipitate B.[1] (c) In Experiment 2, (i) write an equation for the formation of complex ion C[2] (ii) state the type of reaction taking place.[1]OCR 2013<br /> (d) In Experiment 3, 13 (i) write an equation for the formation of complex ion E[2] (ii) state the type of reaction taking place.[1] (e) In Experiment 4, optical isomers F and G are formed. Show the 3-D shapes of F and G. In your diagrams, show the ligand atoms that are bonded to the metal ions and any overall charges. [3] (f) In a separate experiment, iron metal is heated with potassium nitrate, KNO3, a strong oxidising agent. A reaction takes place and the resulting mixture is poured into water. A dark red solution forms containing ferrate(VI) ions. The ferrate(VI) ion has a 2 charge. Suggest a possible formula for the ferrate(VI) ion.[1] [Total: 12]OCR 2013 Turn over<br />

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