CHAPTER 5:
IONIC AND METALLIC BONDS
Some of the following questions assume that a truncated table of reduction half-reactions organized to show the relative strength of reducing and oxidizing agents is attached to the exam under the heading: “potentially useful information.”
Active Metals
5-1. Which of the following metals is the most “active,” the metal which should react most rapidly with oxygen or water vapor in the atmosphere?
(a) Be (b) Ca (c) Ba (d) Al (e) Ga
Answer: (c)
5-2. Which of the following metals would be the most reactive towards air and water?
(a) Ca (b) Al (c) Ag (d) Sn (e) Pb
Answer: (a)
5-3. Which of the following statements is false?
(a) Al reacts rapidly with O2 to form Al2O3
(b) Al2O3 forms a thin coating on the surface of Al metal.
(c) The Al2O3 coating on the surface protects the metal from further corrosion
(d) Al has less affinity for O2 than Fe and therefore doesn’t corrode the way iron metal corrodes when it rusts
(e) none of these statements is false
Answer: (d)
5-4. Which of the following compounds is the least likely to be ionic?
(a) MgF2 (b) MgCl2 (c) MgBr2 (d) MgI2 (e) BaF2
Answer: (c)
5-5. Which reaction doesn’t make chemical sense?
(a) Mg(s) + 2 NH3(l) ➝ Mg(NH2)2(s) + H2(g)
(b) Mg(s) + N2H4(g) ➝ Mg(NH2)2(s)
(c) Mg(s) + 2 HNO3(aq) ➝ Mg(NO3)2(aq) + H2(g)
(d) Mg(s) + 2 NO2(g) + 2 OH-(aq) ➝ Mg(NO3)2(aq) + 2 H+(aq)
Answer: (d)
Reactions with Nonmetal Elements
5-6. Which of the following is the most likely product of the reaction between magnesium metal and nitrogen?
(a) MgN (b) Mg2N (c) MgN2 (d) Mg2N3 (e) Mg3N2
Answer: (e)
5-7. Predict the product of the following reaction: Sr(s) + P4(s).
(a) SrP (b) SrP2 (c) SrP3 (d) Sr2P3 (e) Sr3P2
Answer: (e)
5-8. What would be the product of the reaction between aluminum metal and sulfur?
(a) AlS (b) Al2S (c) AlS2 (d) AlS3 (e) Al2S3
Answer: (e)
5-9. What compound is formed by the reaction of Na with P4?
(a) NaP3 (b) Na3P (c) NaP2 (d) Na2P (e) NaP
Answer: (b)
5-10. Use the positions of silicon and fluorine in the periodic table to predict the most likely product of the reaction between these elements.
(a) SiF (b) SiF2 (c) SiF4 (d) Si2F (e) Si3F4
Answer: (c)
5-11. Use the positions of gallium and oxygen in the periodic table to predict the formula for gallium oxide.
(a) GaO (b) GaO2 (c) GaO3 (d) Ga2O (e) Ga2O3
Answer: (e)
5-12. An element, X, forms the ionic compound CaX. X is a member of:
(a) Group IA (b) Group IIA (c) Group IVA (d) Group VIA (e) Group VIIA
Answer: (d)
5-13. Which of the following elements would be the most likely to form an oxide with the formula XO and a hydride with the formula XH2?
(a) Na (b) Mg (c) Al (d) Si (e) P
Answer: (b)
5-14. An element reacts with hydrogen and oxygen to form ionic compounds with the formulas MH4 and MO2. In which group of the periodic table does this element belong?
(a) IIA (b) IVA (e) VA (d) VIA (e) VIIA
Answer: (b)
5-15. What group of metals react with sulfur to form M2S3 sulfides, react with fluorine to form MF3 fluorides, and react with acid to form M3+ ions and H2 gas?
(a) IA (b) IIA (c) IIIA (d) IVA (e) VA
Answer: (c)
5-16. Which of the following elements would be the most likely to react with hydrogen to form a compound with the formula XH that reacts with water to produce a basic solution and H2 gas?
(a) Na (b) Mg (c) Al (d) Si (e) P
Answer: (a)
5-17. Magnesium metal reacts with hydrogen gas to form a white solid (A) with a high melting point. Compound A reacts with water to form compound B, which is a gas, and an aqueous solution of compound C which is another white solid. Magnesium metal reacts with hydrochloric acid to form gas B and an aqueous solution of compound D. Identify compounds A, B, C and D, and write balanced chemical equations for each reaction.
Answer: MgH2, H2, Mg(OH)2, MgCl2
Reactions with Nonmetal Compounds
5-18. Which of the following equations represents the reaction that would be expected when Ca reacts with water?
(a) Ca(s) + 2 H2O(l) ➝ Ca2+(aq) + 2 OH-(aq)
(b) Ca(s) + 2 H2O(l) ➝ CaH2(aq) + 2 OH-(aq)
(c) Ca(s) + 2 H2O(l) ➝ Ca(OH)2(aq) + 2 H+(aq)
(d) Ca(s) + 2 H2O(l) ➝ Ca(OH)2(aq) + H2(g)
(e) none of these equations corresponds to the reaction expected.
Answer: (d)
5-19. Which of the following describes the products of the reaction of calcium metal and water?
(a) Ca2+, OH- and H2 (b) Ca2+, H- and O (c) Ca2+, H- and OH-
(d) Ca2+ and OH- (e) Ca2+, OH- and H+
Answer: (a)
5-20. Which of the following molecules or ions isn’t formed when K metal reacts with liquid CH3OH?
(a) K+ (b) H+ (c) CH3O- (d) H2
(e) all of these molecules or ions are formed when K metal reacts with CH3OH.
Answer: (b)
5-21. Which of the following wouldn’t be a product of the reaction between potassium metal and an aqueous solution of hydrochloric acid?
(a) K+(aq) (b) H2(g) (c) O2(g) (d) Cl-(aq)
(e) all of the above are products of this reaction.
Answer: (c)
5-22. Which of the following doesn’t form OH- ions when dissolved in water?
(a) LiH (b) Li2CO3 (c) Li2O (d) Li3N
(e) all of the above form OH- ions when dissolved in water.
Answer: (e)
5-23. Which of the following reactions doesn’t occur?
(a) Ca(s) + Cl2(g) ➝ CaCl2
(b) CaO(s) + H2O(l) ➝ Ca(OH)2(aq)
(c) CaH2(s) + 2 H2O(l) ➝ Ca(OH)2(aq) + 2 H2(g)
(d) Ca(s) + 2 H2O(l) ➝ Ca2-(aq) + 2 H3O+(aq)
(e) all of these reactions occur as written.
Answer: (d)
5-24. Which of the following describes the products of the reaction of potassium hydride, KH, with water?
(a) K+, H- and OH- (b) K+, H2 and OH- (c) K+, OH- and H+
(d) K- and H3O+ (e) K and H2
Answer: (b)
5-25. Which of the following describes what happens when sodium hydride is added to water at room temperature?
(a) There is no discernable reaction.
(b) O2 is evolved and the solution becomes basic.
(c) O2 and H2 are evolved and the solution remains neutral.
(d) H2 is evolved and the solution becomes basic.
(e) The solution becomes basic, but no gas is evolved.
Answer: (d)
5-26. What are the products of the reaction between sodium peroxide and water?
(a) sodium, oxygen and hydrogen
(b) sodium hydroxide and oxygen
(c) sodium hydroxide and hydrogen
(d) sodium oxide and hydrogen
(e) an aqueous solution of sodium peroxide
Answer: (e)
5-27. Which of the following describes the products of the reaction of Na2O with water?
(a) Na+ and O2- (b) Na+, H2 and OH- (c) Na and OH-
(d) Na+, H2 and H+ (e) Na and O2
Answer: (c)
5-28. Which of the following isn’t formed when potassium metal reacts with liquid phosphine?
K(s) + PH3(l) ➝
(a) K+ ions (b) PH2- ions (c) H2 gas (d) H+ ions
(e) all of the above are formed in this reaction
Answer: (d)
5-29. Which of the following ions or molecules aren’t formed when Li3N dissolves in water?
(a) Li+(aq) (b) H+ (c) OH-(aq) (d) NH3(aq)
(e) all of the above are formed in this reaction
Answer: (b)
Redox Reactions
5-30. Which of the following compounds has sulfur in a +6 oxidation state?
(a) SO2 (b) H2S (c) H2SO3 (d) H2SO4 (e) H2S2O3
Answer: (d)
5-31. For the reaction: 3 S(s) + 2 KClO3(s) ➝ 3 SO2(g) + 2 KCl(s), which of the following is true?
(a) S is reduced. (b) KClO3 is the reducing agent. (c) S is the oxidizing agent.
(d) All of the above are true. (e) None of the above are true.
Answer: (e)
5-32. In the following oxidation-reduction reaction,
Sr(s) + 2 H2O(l) ➝ Sr2+(aq) + 2 OH-(aq) + H2(g)
which of the following statements is true.
(a) H2O is oxidized
(b) Sr acts as the oxidizing agent
(c) H2 is reduced
(d) H2O is the oxidizing agent
(e) more than one of the above is true
Answer: (d)
5-33. Phosphorus is reduced in which of the following reactions?
(a) P4(s) + 5 O2(g) ➝ P4O10(s)
(b) P4(s) + 3 O2(g) ➝ P4O6(s)
(c) P4(s) + 6 F2(g) ➝ 4 PF3(g)
(d) P4(s) + 6 Ca(s) ➝ 2 Ca3P2(s) + H2O(l)
(e) P4(s) + 6 Cl2(g) ➝ 4 H3PO3(aq) + 12 HCl(aq)
Answer: (d)
5-34. Which isn’t an oxidation-reduction reaction?
(a) 2 Na + Cl2 ➝ 2 NaCl
(b) 2 HCl ➝ H2 + Cl2
(c) 2 NO2 + H2O ➝ HNO3 + HNO2
(d) Na2CO3 + 2 HCl ➝ 2 NaCl + CO2 + H2O
(e) all of these are oxidation-reduction reactions.
Answer: (d)
5-35. Which of the following reactions involves oxidation-reduction? For those that are redox reactions, identify which reagent is oxidized and which reagent is reduced.
(a) Ca3P2(s) + 6 H2O(l) ➝ 3 Ca(OH)2(aq) + 2 PH3(g)
(b) 2 PH3(g) + 4 O2(g) ➝ H3PO4(s)
(c) PH3(g) + HCl(g) ➝ PH4Cl(s)
(d) P4(s) + 5 O2(g) ➝ P4O10(s)
Answer: b and d
Oxidizing/Reducing Agents
5-36. Which of the following statements about the following reaction is false?
2 Na(s) + 2 NH3(l) ➝ 2 NaNH2(s) + H2(g) is/are false?
(a) Na is the reducing agent
(b) NH3 is oxidized
(c) Na is a better reducing agent than H2
(d) There is no change in the oxidation state of the nitrogen.
(e) This isn’t a redox reaction.
Answer: (b)
5-37. Identify the reducing agent and oxidizing agent in the reaction:
H2O2(aq) + 2 HI(aq) ➝ 2 H2O(l) + I2(s)
Answer: OA = H2O2, RA = HI
5-38. Identify the conjugate oxidizing agent for each of the following reducing agents.
(a) Na (b) Zn (c) H- (d) Sn2+
Answer: Na+, Zn2+, H2, Sn4+
5-39. Use the table of relative reducing strengths on the front page to determine which (if any) of the following reactions should occur as written.
(a) Mg(s) + 2 NaCl(s) ➝ MgCl2(s) + 2 Na(s)
(b) 3 Na(s) + AlCl3(l) ➝ 3 NaCl(s) + Al(s)
(c) Al2O3(s) + 2 Fe(s) ➝ Fe2O3(s) + 2 Al(s)
(d) All of these reactions should occur as written.
(e) None of these reaction should occur as written.
Answer: (b)
5-40. Which (if any) of the following reactions should occur as written?
(a) Pb(s) + 2 NaCl( s) ➝ PbCl2(s) + 2 Na(s)
(b) 4 Na(s) + AlCl3(l) ➝ 3 NaCl(s) + Al(s)
(c) Al2O3(s) + 2 Fe(s) ➝ Fe2O3(s) + 2 Al(s)
(d) all of these reactions should occur as written.
(e) none of these reaction should occur as written.
Answer: (b)
5-41. Which of the following reducing agents aren’t strong enough to reduce Fe2O3 to iron metal?
(I) Na (II) Mg (III) Al (IV) Ag (V) H2
(a) I and II (b) I and III (c) II and III
(d) III and IV (e) IV and V
Answer: (e)
5-42. Which of the following oxides can be reduced to the metal with H2?
(a) Na2O (b) MgO (c) Al2O3 (d) Fe2O3 (e) HgO
Answer: (e)
5-43. Which of the following reducing agents should be able to reduce Sn2+ ions to tin metal?
(I) Na (II) Mg (III) Al (IV) Fe (V) Hg
(a) I and II (b) I, II and III (c) II and III (d) I, II, III and IV
(e) all of these reducing agents should be able to reduce Sn2+ ions to tin metal.
Answer: (d)
5-44. The relative strength of various oxidizing and reducing agents is summarized in the following table.
K+ + e- ➝ K
Na+ + e- ➝ Na
Al3+ + 3 e- ➝ Al
Zn2+ + 2 e- ➝ Zn
Fe3+ + 3 e- ➝ Fe
2 H+ + 2 e- ➝ H2
Cu2+ + 2 e- ➝ Cu
Ag+ + e- ➝ Ag
Which element or ion is the strongest reducing agent in this table?
(a) K+ (b) K (c) H2 (d) Ag+ (e) Ag
Answer: (b)
5-45. According to this table, which of the following reactions will occur as written?
(a) Zn(s) + 2 NaCl(s) ➝ ZnCl2(s) + 2 Na(s)
(b) Fe2O3(s) + 3 Cu(s) ➝ 2 Fe(s) + 3 CuO(s)
(c) 3 K(s) + AlCl3(s) ➝ 3 KCl(s) + Al(s)
(d) all of these reactions will occur as written.
(e) none of these reactions will occur as written.
Answer: (c)
5-46. HgO decomposes to mercury metal when heated. CuO doesn’t decompose on heating but can be reduced to copper metal with elemental carbon or hydrogen. Al2O3 cannot be reduced to aluminum metal with either carbon or hydrogen. Arrange these three metals in order of increasing activity.
Answer: Al > Cu > Hg
Preparing Metals
5-47. Which metal isn’t manufactured by electrolysis?
(a) Na (b) Mg (c) Al (d) Zn (e) Fe
Answer: (e)
5-48. Metal ores are roasted to convert sulfides into the corresponding oxides.
2 ZnS(s) + 3 O2(g) ➝ 2 ZnO(s) + 2 SO2(g)
Is this an oxidation-reduction reaction? What is oxidized or reduced?
Answer: S2- is oxidized, O2 is reduced
Lattice Energies
5-49. Which of the following is the best explanation for the reaction between Na and Cl2 to form NaCl?
(a) Sodium likes to give up electrons to form Na+ ions.
(b) Enough energy is given off when neutral chlorine atoms pick up an electron to form Cl- ions to remove an electron from a neutral sodium atom to form a Na+ ion.
(c) It takes a enormous amount of energy to generate Na+ and Cl- ions, but, once this is done, even more energy is given off when these ions come together to form an ionic lattice.
(d) Chemists would argue that the above explanations are all equally valid.
(e) None of the above explanations are valid.
Answer: (c)
5-50. The lattice energy of NaCl is a measure of the energy given off in which of the following reactions?
(a) Na(s) + Cl2(s) ➝ 2 NaCl(s)
(b) Na+(s) + Cl-(s) ➝ NaCl(s)
(c) Na(g) + Cl(g) ➝ NaCl(g)
(d) Na+(g) + Cl-(g) ➝ NaCl(g)
(e) Na+(g) + Cl-(g) ➝ NaCl(s)
Answer: (e)
5-51. Which of the following compounds will have the smallest lattice energy?
(a) CsI (b) NaI (c) NaF (d) BaTe (e) MgO
Answer: (a)
5-52. Which of the following ionic solids would have the highest lattice energy?
(a) NaI (b) MgS (c) BeO (d) CsBr (e) MgO
Answer: (c)
5-53. Which of the following has the largest lattice energy? (Assume the negative ions are all approximately the same size.)
(a) NaClO4 (b) Na2SO4 (c) NaH2PO4 (d) Na3PO4 (e) CsClO4
Answer: (d)
5-54. The lattice energy of Cs2Te (interatomic distance = 0.390 nm) should be closest to that of:
(a) CsI (interatomic distance = 0.385 nm)
(b) Cs2O (interatomic distance = 0.309 nm)
(c) LiF (interatomic distance = 0.196 nm)
(d) Li2Te (interatomic distance = 0.281 nm)
(e) SrI2 (interatomic distance = 0.400 nm)
Answer: (e)
Oxidation Numbers
5-55. What is the maximum possible oxidation state of a P atom?
(a) +2 (b) +3 (c) +4 (d) +5 (e) none of the above
Answer: (d)
5-56. What is the oxidation state of the Mo atom in Li2MoO4?
(a) 0 (b) +2 (c) +4 (d) +5 (e) +6
Answer: (e)
5-57. All but one of the following species contains nitrogen in the same oxidation state. Which one is different?
(a) HNO2 (b) NH2- (c) NH3 (d) NH4Cl (e) Na3N
Answer: (e)
5-58. An area of active research interest in recent years has been compounds such as Re2Cl82-, Cr2Cl93-, and Mo2Cl84- that contain metal-metal bonds. Calculate the oxidation number of the metal atom in each of these compounds.
Answer: Re = +3; Cr = +3, Mo = +2
5-59. The active ingredient in Rolaids has the formula NaAl(OH)2CO3. Calculate the oxidation state of the aluminum atom in this compound.
(a) -3 (b) 0 (c) +1 (d) +2 (e) +3
Answer: (e)
5-60. Arrange the following compounds in order of increasing oxidation state for the carbon atom: CO, CO2, H2CO, CH3OH, CH4
Answer: CH4 < CH3OH < H2CO < CO < CO2
5-61. Which compounds contain hydrogen in a negative oxidation state?
(I) H2S (II) PH4+ (III) LiAlH4 (IV) CH4 (V) CaH2
(a) I, II and IV (b) II, III and IV (c) III and IV (d) III and V
(e) none of these contain hydrogen in a negative oxidation state
Answer: (d)
5-62. Prussian blue is a pigment with the formula: Fe4[Fe(CN)6]3. If this compound contains the [Fe(CN)6]4- ion, what is the oxidation state of the other four iron atoms? Turnbull's blue is a pigment with the formula Fe3[Fe(CN)6]2. This compound contains the [Fe(CN)6]3- ion. What is the oxidation state of the other three iron atoms?
(a) Prussian blue = -3, Turnbulls blue = -2 (b) Prussian blue = 2, Turnbulls blue = 2
(c) Prussian blue = 2, Turnbulls blue = 3 (d) Prussian blue = 3, Turnbulls blue = 2
(e) Prussian blue = 3, Turnbulls blue = 3
Answer: (d)
5-63. Honda and Toyota both sell hybrid cars that have engines that can run on either gasoline or electricity stored in a battery. (Both companies are “losing their shirts” on these cars because so few are being sold.) The advantage of hybrid cars is simple: Totally electric cars need batteries that weigh almost as much as the vehicle!) It isn’t surprising that a high priority is the search for better batteries. Barium ferrate (BaFeO4) is being tested for use in batteries. Use the positions of barium and oxygen in the periodic table to predict the oxidation state of the iron atom in this so-called “super-iron” compound.
(a) +2 (b) +3 (c) +4 (d) +6 (e) +8
Answer: (d)
5-64. When Apple™ released its Powerpoint™ laptop there was a problem with some of the lithium ion batteries catching fire. One of the compounds being studied for use as an electrode in lithium ion batteries being developed for use in the next generation of portable computers has the following empirical formula: LiMnO4. What is the oxidation state of the manganese atom in this compound?
(a) +2 (b) +3 (c) +4 (d) +5 (e) +7
Answer: (e)
5-65. Only 15% of the energy a gallon of gasoline is used to move a vehicle. It isn’t surprising that batteries are being developed to store more energy on-board the vehicle and to use the energy more efficiently. Two directions in which the search is going are lithium ion and nickel metal hydride batteries. Lithium ion batteries are high energy density, 3.6 V batteries that use a lithium salt such as LiCoO2 or LiPF6 for the positive electrode, or cathode. Use the positions of lithium and fluorine in the periodic table to predict the oxidation state of the phosphorus atom in LiPF6.
(a) +1 (b) +2 (c) +3 (d) +4 (e) +5
Answer: (e)
Nomenclature
5-66. What is the correct name for Ca(NO3)2?
(a) calcium nitride (b) calcium nitrite (c) calcium nitrate
(d) calcium dinitrite (e) calcium dinitrogen hexaoxide
Answer: (c)
5-67. The name for Li3N is:
(a) lithium nitride (b) lithium(II) nitride (c) lithium(III) nitride
(d) lithium trinitride (e) trilithium nitride
Answer: (a)
5-68. Which of the following formula/name combinations is incorrect?
(a) H2SO3/sulfurous acid (b) HCO3-/bicarbonate ion
(c) HBrO3/bromic acid (d) ClO4-/hypochlorate ion
(e) CuSO4/copper(II) sulfate
Answer: (d)
5-69. What is wrong with the common names for the following compounds? Write a better name for each compound.
(a) phosphorus pentoxide (P2O5) (b) iron oxide (Fe2O3)
(c) sodium carbonate (NaHCO3) (d) chlorine monoxide (Cl2O)
(e) copper bromide (CuBr2)
Answer: (a) you get the wrong formula from the name; (b) you don’t know whether
this is Fe2+ or Fe3+; (c) this is a bicarbonate or hydrogen carbonate salt
(d) you get the wrong formula from this name; (e) this is copper(II) bromide
5-70. Explain why CaBr2 is calcium bromide but FeBr2 has to be called iron(II) bromide.
Answer: Calcium is typically Ca2+, but iron is either Fe2+ or Fe3+
5-71. Write the formulas for:
(a) tetraphosphorus trisulfide (b) silicon dioxide
(c) carbon disulfide (d) carbon tetrachloride (e) phosphorus pentafluoride
Answer: P4S3; SiO2; CS2; CCl4; PF5
5-72. Write the formulas for:
(a) silicon tetrafluoride (b) sulfur hexafluoride
(c) oxygen difluoride (d) dichlorine heptoxide (e) chlorine trifluoride
Answer: SiF4; SF6; OF2; Cl2O7, ClF3
5-73. Write the formulas for:
(a) tin(II) chloride (b) mercury(II) nitrate (c) tin(IV) sulfide
(d) chromium(III) oxide (e) iron(II) phosphide
Answer: SnCl2; Hg(NO3)2; SnS2; Cr2O3; Fe3P2
5-74. Name the following:
(a) KNO3 (b) Li2CO3 (c) BaSO4 (d) Na2SO3 (e) Pbl2
Answer: potassium nitrate, lithium carbonate, barium sulfate,
sodium sulfite, lead(II) iodide
5-75. Name the following:
(a) AlCl3 (b) Na3N (c) Ca3P2 (d) Li2S (e) MgO
Answer: aluminum chloride, sodium nitride, calcium phosphide,
lithium sulfide, magnesium oxide
5-76. Name the following:
(a) Sb2S3 (b) SnCl2 (c) SF4 (d) SrBr2 (e) SiCl4
Answer: antimony sulfide, tin(II) chloride, sulfur tetrafluoride,
strontium bromide, silicon tetrachloride
5-77. Write the formulas of the following common acids:
(a) acetic (b) hydrochloric (c) sulfuric (d) phosphoric (e) nitric
Answer: CH3CO2H, HCl, H2SO4, H3PO4, HNO3