Name: __________________________Page 1 of 13Chemistry 142 Electrochem & Coordination Chem Practice (Exam #3 Review)Part I ElectrochemistryQuestion 1. Balance the following redox reactions.a) HI + HNO3 → I2 + NOb) Ag + H2SO4 → Ag2SO4 + SO2c) MnCl2 + KMnO4 + KOH → MnO2 + KCld) H3AsO4 + Zn + HNO3 → AsH3 + Zn(NO3)2e) P4 + NaOH → NaH2PO4 + PH3Name: __________________________Page 2 of 13Question 2. Potassium was discovered by Sir Humphry Davy when he electrolyzed molten potassium hydroxide. Showthis electrolytic cell and the electrode reactions.Question 3. An iron rod is placed in 1.0M iron(III) chloride solution and a zinc rod is placed in a 1.0M zinc sulfatesolution. Diagram this cell, give the cell potential, and give the shorthand notation.Name: __________________________Page 3 of 13Question 4. Calculate the standard free energy change, using electrochemical potentials, for the reaction,Na(s) + ½ Cl2(g) → Na+ + Cl–Question 5. What is the emf of the following cell?Ni(s)|Ni2+(1.0M)||Sn2+(1.0×10–4M)|Sn(s)Question 6. Calculate the equilibrium constant for the following reaction at 298 K.Fe3+ + Sn2+ → Fe2+ + Sn4+Name: __________________________Page 4 of 13Question 7. The commercial production of Cl2 involves the electrolysis of aqueous NaCl solutions. Give the products ofthis electrolysis at each electrode and calculate how long it will take to produce 1.18 kg of Cl2 when acurrent of 5.00×102 A is applied.Question 8. Diagram a lead-acid storage battery. Show the reactions that occur at each electrode and calculate the cellpotential.Question 9. What is a sacrificial anode?Name: __________________________Page 5 of 13Part II Coordination ChemistryQuestion 1. Write the formula for the complex ion, and the coordination compounds containing the indicated centralatom, ligands, and counter ion.a) central atom: Fe3+, ligands: six CN–, counter ion: K+b) central atom: Ag+, ligands: two OH–, counter ion: Na+c) central atom: Ni2+, ligands: four NH3, counter ion: SO42–d) central atom: Pt4+, ligands: four H2O, two Cl–, counter ion: Cl–Name: __________________________Page 6 of 13Question 2. Find the coordination number and oxidation number of the central atom in each coordination compoundbelow.Question 3. In the blanks give the formula indicating the composition of the complex and the counter ions for thecoordination compounds below.Question 4. Complete the table belowCentral Atom Oxidation No. Coordination No.K2[PtCl6][Fe(H2O)6](NO3)2Na2[Ni(CN)4][Zn(H2O)2(OH)2]Compositionmoles Cl–/mol compoundTotal no. of ionsFormula of Coord. CompoundPtCl4(NH3)6four five[Pt(NH3)6]Cl4PtCl4(NH3)4two threePtCl4(NH3)2none onePtCl4(NH3)Knone twoForm. of Coord. CompoundFormula of Complex Ion Formula of Counter Ion Total No. of Ions[Cr(H2O)6]Cl3[Cr(H2O)5Cl]Cl2[Cr(H2O)4Cl2]ClNH4[Cr(H2O)2Cl4]Name: __________________________Page 7 of 13Question 5. For each complex below, give the coordination number of the central atom, and the expected geometry ofthe complex.Question 6. Draw structures for the two isomers of [Ni(NH3)2(H2O)3]2+.Question 7. Draw structures for the two isomers of [Pt(H2O)2(NH3)Cl]+.Coord. No. of Central Atom Geom. of Complex[Fe(H2O)6]3+[Ni(NH3)2Cl2](only one isomer)[Ni(H2O)3(NH3)3]2+[Au(CN)2Cl2]–(two isomers)Name: __________________________Page 8 of 13Question 8. Give the oxidation number and coordination number of the central atom in each complex below.Question 9. Draw structures for the two isomers of [Cr(C2O4)2(H2O)2]–Complex Ox. No. of Central Atom Coord. No. of Central Atom[Ni(en)3]2+[Co(CO3)3]3–[Pt(C2O4)2]2–[Ni(dmg)2]Name: __________________________Page 9 of 13Question 10. Name each of the following.Question 11. Write the formula for the following compounds.a) hexaamminenickel(II) sulfateb) dichlorobis(ethylenediamine)cobalt(III) chloride[Cu(NH3)4]SO4[Co(H2O)4Br2]BrK[Cr(NH3)2Cl4]Na2[Zn(OH)4]K3[Co(C2O4)3]Name: __________________________Page 10 of 13Question 12. What is the color of a substance that absorbs yellow light?Question 13. The substance that gives leaves their green color is chlorophyll. Approximately what wavelength of lightdoes chlorophyll absorb?Question 14. In each pair of substances below, circle the one that absorbs light of higher energy. The observed color ofeach substance is indicated.a) Substance A (yellow), substance B (green)b) Substance B (green), substance C (violet)c) Substance D (red), substance E ( blue)d) Substance C (violet), substance F (orange)Name: __________________________Page 11 of 13Question 15. Draw the crystal field splitting diagrams for [Ni(H2O)6]2+, which is green, and[Ni(NH3)6]2+, which is blue.Label the d-orbitals and place the nickel(II) valence electrons into the orbitals. Show only the ground stateconfiguration.Question 16. Which complex has the larger Δ?Question 17. What is the approximate value of Δ in kJ/mol for [Ni(H2O)6]2+? Use the color of the complex to estimate thevalue.Name: __________________________Page 12 of 13Question 18. Consider the two complex ions, [Mn(H2O)6]2+ and Mn[(CN)6]4–. The first is pale red and is a high-spincomplex, while the second is a low-spin complex. a) Sketch the crystal field splitting energy diagram for [Mn(H2O)6]2+. Label each orbital and put in theelectron.b) Do the same for Mn[(CN)6]4–.c) What is the color of the light absorbed by [Mn(H2O)6]2+?d) Based on the magnitude of its Δ compared to that of the H2O complex, what color of light might beabsorbed by [Mn(CN)6]4–?e) What color is a solution of [Mn(CN)6]4– likely to be?Name: __________________________Page 13 of 13Question 19. The magnitude of splitting of orbital energies of a transition metal ion depend upon the identity of the ligand.Based on the color of the complexes in the table below, arrange the ligands in order of the magnitude ofsplitting they cause, beginning with the ligand causing the smallest Δ.Least ____________ < ____________ < ____________ < ___________ GreatestQuestion 20. Ni(CN)42– is yellow and has no unpaired electrons. NiCl42– is deep blue and has two unpaired electrons.a) Which complex is high spin and which is low spin?b) What is the correct geometry for each complex ion?c) Sketch the correct splitting energy diagram for each complex ion. Label each orbital and fill in theelectrons.Complex Color Complex Color[Co(H2O)6]3+pale red[Co(CN)6]3–yellow[Co(NH3)6]3+pale