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國立彰化師範大學九十四學年度碩士班招生考試試題 系所:化學系 科目: 無機化學與分析化學 ☆☆請在答案紙上作答☆☆ 共 2 頁,第 1 頁 1. Write octet structure (including formal charges, bond order, and molecular shape) for Al2Cl6, SnCl3-, BrF4-. (6 %) 2. The hypofluorite ion, OF-, is quite unstable compared to OCl-. (a) Draw a molecular orbital energy level diagram for OF-. (b) What is the bond order in OF-, and how many unpaired electrons are there? (c) Why do you think OF- is so unstable? (7 %) 3. Explain briefly the observed rate of exchange of H2O from the metal ions of the 4th period. (5 %) K+ Ca2+ Sc3+ Ti3+ Cr3+ Fe3+ 109s-1 3x108 s-1 5x107 s-1 105 s-1 10-6 s-1 104 s-1 4. (a) For Oh complexes, π acceptor ligands increase Δ0, while π donor ligands decrease Δ0.. Use energy level diagrams to explain why. Be sure to show Δ0 in the diagrams. (b). Put in the order of increasing ligand field strength: H2O, F-, Cl-, NSC- (nitrogen coordinate), CO, Br-. (5 %) 5. Draw product of the following reactions and give name to each reaction. (6 %) (a) Mn(CO)5(C2H5) + CO (b) trans-Ir(PR3)2(CO)(Cl) + H3CBr (c) Co2(CO)8 + Na 6. Draw the structure and assign the point groups for the following molecules. (8 %) (a) IF7 (b) AlCl3 (c) NHClF (d) IF27. Put the following chemical species into their proper place in the HSAB table (5 %) F-, Mg2+,H2O, CN-, Cr3+, SO42-, Br-,R2S, Cd2+, Fe2+. Acid Base Hard Borderline Soft 8. Sketch all the possible geometrical isomers for the following complexes and indicate which of these would exhibit optical activity. (6 %) (a) [Co(NH2CH2CO2)2(NH3)Cl]+ (b) [Pt(NH3)BrCl(NO2)](c) [Co(trien)Cl2]+ 9. Assign an outer- or inner-sphere mechanism for each of the following reaction and briefly explain your assignments. (6 %) (a) The main product of the reaction between [Cr(NCS)F]+ and Cr2+ is CrF2+. (b) The rate of reduction of [Co(NH3)5py]3+ by [Fe(CN)6]4+ are insensitive to substitution on py. (c) The rate of reduction of [Co(NH3)5NCS]2+ by Ti3+ is 36000 times smaller than the rate of [Co(NH3)5N3]2+ reduction. -1- 國立彰化師範大學九十四學年度碩士班招生考試試題 系所:化學系 科目: 無機化學與分析化學 ☆☆請在答案紙上作答☆☆ 共 2 頁,第 2 頁 10. For each of the following elements, identify one significantly role in biological processes: Fe, Mn, Cu, Ni, Mo, Zn. (6 %) 11. Calculate the pH of 1.00 M HCl solution. (5 %) 12. Explain how the laser generates light. What is meant by population inversion in laser action? (10 %) 13. What would be the effect of the following on the “plate height” of a column in gas chromatography? Explain! (6 %) (a) Increasing the weight of the stationary phase relative to the packing weight. (b) Decreasing the rate of sample injection. 14. Calculate the voltage of the cell: (8 %) Cu(s)∣Cu2+ (0.030M) || K+Ag (CN)2- (0.010 M), HCN (0.10 M), buffer to pH 8.21∣Ag(s). Ag (CN)2- + e = Ag(s) + 2CN-. E° = -0.310 V; HCN (aq) = H+ + CN-, pKa = 9.21; Cu2+ + 2e = Cu(s), E° = -0.339 V. 15. Hydrogen has to stable isotopes, 1H and 2H. Sulfur has four stable isotopes, 32S, 33S, 34S, and 36S. How many peaks would you observe in the mass spectrum of the positive ion of H2S+? Explain your answer. Assuming no decomposition of the ion into smaller fragments. (5 %) 16. An indicator H4In is to be used as a metal ion indicator in an EDTA direct titration. From the following available buffers: (a) pH 1~2, (b) pH 2~3, (c) pH 3~6, (d) pH 7~10 (e) pH 11~13, select the best buffer and explain your answer. The color of metal-indicator complex is red, and the colors and values of pKa of indicator are shown below: H4In(yellow) H3In-(yellow) H2In2-(yellow) HIn3-(violet) In4-(violet) pK1 = 2.32 pK2 = 2.85 pK3 = 6.70 pK4 = 10.47 Assume no other reaction exists except metal-indicator complexation and acid dissociations. (6 %) -2-