A number of isomers with the formula Cr(H2O)6Cl3 exist. Their general formula is [Cr(H2O)6-nCln]Cl3-n.nH2O. Each isomer contains a six co-ordinated Cr(III) ion in an octahedral complex. Water molecules not directly bonded with the Cr atom are held in the crystal lattice as water of crystallisation. The Cr-Cl bond is not easily broken and so chloride bonded with the Cr(III) ion in the complex does not react. 1.00g samples of three of the isomers, A, B and C, were dissolved in separate samples of water. An excess of AgNO3(aq) was added to each and the mass of AgCl(s) formed was measured. Ag+(aq) + Cl-(aq) → AgCl(s) The number of moles of AgCl(s) formed was calculated. The table shows the results. isomer moles of AgCl formed from 1.00 g of isomer A 3.75 x 10-3 B 7.50 x 10-3 C 1.13 x 10-2

1. (a)(i)Calculate the Mr of Cr(H2O)6Cl3. Mr Cr(H2O)6Cl3 = ...[1]
2. (a)(ii)Use the data in the table above to calculate the value of n for each of the isomers, A, B and C. Complete the table below with the values of n and the molecular formula of each isomer, in the style of the general formula given above. Show your working for at least one calculation of n. isomer n molecular formula A B C[2]
3. (b)(i)Name the type of isomerism shown by Ni(R3P)2(CN)2.[1]
4. (b)(ii)Draw structures of these two isomers. isomer 1 isomer 2[1]
5. (b)(iii)State which isomer has a dipole moment. Explain your answer.[1]

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