(Eonta) Reactions on Aqueous Reactions

Review Questions — Chapter 5 — Reactions in Solution

Chapter 5REACTIONS IN AQUEOUS SOLUTION

5-1. Which one of the following is a nonelectrolyte when dissolved in water?(a) sodium chloride (b) sugar(c) copper sulfate (d) calcium chloride

5-2. Which of the following is predicted to be insoluble in water?(a) NaBr (b) NH4Cl(c) FeS (d) (NH4)2S

5-3. Which of the following is predicted to be soluble in water?(a) Fe(OH)3 (b) AgCl(c) CaCl2 (d) BaSO4

5-4. In which set of compounds below are all the compounds insoluble in water?(a) NaCl, AgCl, ZnCl2 (b) Na2CO3, CaCO3, (NH4)2CO3(c) (NH4)2S, FeS, Na2SO4 (d) ZnS, NiS, CoCO3

5-5. If you want to make a water-soluble salt using the zinc(II) cation, Zn2+, what anion wouldyou choose?(a) NO3

- (b) CO32-

(c) C2O42- (d) PO4

3-

5-6. If you want to make a water-insoluble salt using the nickel(II) ion, what anion would younot choose?(a) S2- (b) Cl-

(c) PO43- (d) CO3

2-

5-7. Which compound below is an acid in aqueous solution?(a) CH4 (b) K2CO3(c) NaOH (d) HNO3

5-8. Which of the compounds below is not an acid in aqueous solution?(a) CH3COOH (b) H3PO4(c) NH3 (d) HCl

5-9. Which compound below is a base in aqueous solution?(a) CH4 (b) KCl(c) NaOH (d) HNO3

Revised: October 21, 1998


5-10. Which compound below is not a base in aqueous solution?(a) KOH (b) H2SO4(c) Ca(OH)2 (d) NH3

5-11. Which equation below illustrates the reaction of an acid in aqueous solution?(a) NaOH(aq) → Na+(aq) + OH-(aq)

(b) NH3(aq) + H

2O(l) → NH

4+(aq) + OH-(aq)

(c) HNO3(aq) + H

2O(l) → H

3O+(aq) + NO

3-(aq)

(d) HCl(aq) + H2O(l) → H

2Cl+(aq) + OH-(aq)

5-12. Which equation below best represents the balanced, net ionic equation for the reaction ofpotassium hydroxide and iron(II) chloride to give iron(II) hydroxide and potassiumchloride?(a) 2 KOH(aq) + FeCl

2(aq) → Fe(OH)

2(s) + 2 KCl(aq)

(b) 2 KOH(aq) + FeCl2(aq) → Fe(OH)

2(aq) + 2 KCl(aq)

(c) 2 OH-(aq) + Fe2+(aq) → Fe(OH)2(s)

(d) K+(aq) + Cl-(aq) → KCl(aq)

5-13. Which equation below best represents the balanced, net ionic equation for the reaction ofmagnesium carbonate with nitric acid.(a) MgCO

3(s) + 2 HNO

3(aq) → Mg(NO

3)2(aq) + CO

2(g) + H

2O(l)

(b) MgCO3(s) + 2 H

3O+(aq) → Mg2+(aq) + CO

2(g) + 3 H

2O(l)

(c) Mg2+(aq) + 2 NO3

-(aq) → Mg(NO3)2(s)

(d) MgCO3(s) + HNO

3(aq) → Mg(NO

3)2(aq) + H

2CO

3(aq)

5-14. What are the products obtained on mixing aqueous solutions of KOH and HNO3?(a) KNO3(aq) and water(b) KNO3(s) and water(c) K2O and NO(d) there is no net chemical reaction

5-15. What are the products obtained on mixing aqueous solutions of Ni(NO3)2 and (NH4)2S?(a) NiS(aq) and NH4NO3(s) (c) Ni2S(s) + (NH4)2NO3(aq)(b) NiS(s) and NH4NO3(aq) (d) there is no net chemical reaction



5-16. Which of the following best represents the equation for the reaction of aqueous ammoniaand sulfuric acid?(a) NH

3(aq) + H

2SO

4(aq) → H

3SO

4+(aq) + NH

2-(aq)

(b) NH3(aq) + H

2SO

4(aq) → NH

4SO

4(aq)

(c) 2 NH3(aq) + H

2SO

4(aq) → (NH

4)2SO

4(aq)

(d) there is no net chemical reaction

5-17. Which of the following does not represent a way to prepare sodium sulfate?(a) 2 NaCl(aq) + H

2SO

4(aq) → Na

2SO

4(aq) + 2 HCl(aq)

(a) Na2CO

3(s) + H

2SO

4(aq) → Na

2SO

4(aq) + H

2O(l) + CO

2(g)

(c) 2 NaOH(s) + H2SO

4(aq) → Na

2SO

4(aq) + 2 H

2O(l)

(d) Na2S(s) + CuSO

4(aq) → Na

2SO

4(aq) + CuS(s)

5-18. Assume you dissolve 6.73 g Na2CO3 in enough water to make 250. mL of solution. (Molar mass of Na2CO3 = 106 g/mol.) What is the molarity of the sodium carbonate?(a) 26.9 M (b) 0.0635 M(c) 0.254 M (d) 0.762 M

5-19. We have dissolved 2.335 g of K2Cr2O7 (molar mass = 294.18 g/mol) in enough water tomake 500. mL of solution. What is the molarity of the potassium dichromate?(a) 1.59 x 10 -5 M (b) 0.00794 M(c) 0.0318 M (d) 0.0159 M

5-20. If you have 250. mL of a 0.0125 M solution of KMnO4 (molar mass = 158.03 g/mol),how many grams of solute do you have? (a) 0.494 g (b) 3.13 g(c) 0.247 g (d) 1.98 g

5-21. How many grams of solute are there in 100. mL of a 1.023 x 10-3 M solution of Na3PO4(molar mass = 163.94 g/mol)?(a) 16.8 g (b) 0.0168 g(c) 1.00 x 10 -4 g (d) 0.168 g

5-22. How many milliliters of 0.123 M NaOH solution contain 25.0 g of NaOH (molar mass =40.00 g/mol)?(a) 50.80 mL (b) 625 mL(c) 5080 mL (d) 7.69 mL

5-23. If you add 4.00 mL of pure water to 6.00 mL of 0.0250 M CuSO4, what is theconcentration of copper(II) sulfate in the diluted solution?(a) 0.0150 M (b) 0.00417 M(c) 0.0100 M (d) 0.0375 M



5-24. If you need 1.00 L of 0.125 M H2SO4, how would you prepare this solution?(a) Dilute 36.0 mL of 1.25 M H2SO4 to a volume of 1.00 L(b) Dilute 20.8 mL of 6.00 M H2SO4 to a volume of 1.00 L(c) Add 950. mL of water to 50.0 mL of 3.00 M H2SO4(d) Add 500. mL of water to 500. mL of 0.500 M H2SO4

5-25. What are the ion concentrations in a 0.12 M solution of BaCl2?

(a) [Ba2+] = 0.12 M and [Cl-] = 0.12 M(b) [Ba2+] = 0.12 M and [Cl-] = 0.060 M(c) [Ba2+] = 0.12 M and [Cl-] = 0.24 M(d) [Ba2+] = 0.0.060 M and [Cl -] = 0.060 M

5-26. What are the ion concentrations in a 0.24 M solution of Na3PO4?

(a) [Na+] = 0.24 M and [PO43-] = 0.24 M

(b) [Na+] = 0.060 M and [PO43-] = 0.18 M

(c) [Na+] = 0.080 M and [PO43-] = 0.24 M

(d) [Na+] = 0.72 M and [PO43-] = 0.24 M

5-27. What is the total concentration of ions in a 0.0360 M solution of Na2CO3?(a) 0.0900 M (b) 0.108 M(c) 0.0120 M (d) 0.0720 M

5-28. How many grams of BaCl2 (molar mass = 208.2 g/mol) do you have to add to 250.0 mLof water to have a chloride ion concentration of 0.0125 M?(a) 0.325 g (b) 1.30 g(c) 0.163 g (d) 5.21 g

5-29. How many grams of Na2CO3 (molar mass = 106.0 g/mol) are required for completereaction with 25.0 mL of 0.155 M HNO3?

Na2CO

3(aq) + 2 HNO

3(aq) → 2 NaNO

3(aq) + CO

2(g) + H

2O(l )

(a) 0.410 g (b) 205 g(c) 0.205 g (d) 0.122 g

5-30. How many milliliters of 0.125 M HNO3 are required to react completely with 1.30 g ofBa(OH)2 (molar mass = 171.34 g/mol)?

2 HNO3(aq) + Ba(OH)

2(s) → Ba(NO

3)2(aq) + 2 H

2O(l )

(a) 1.90 mL (b) 60.7 mL(c) 356 mL (d) 121 mL



5-31. An aqueous solution of NaCl gives H2(g), Cl2(g), and NaOH when an electrical current ispassed through the solution. 2 NaCl(aq) + 2 H

2O(l ) → H

2(g) + Cl

2(g) + 2 NaOH(aq)

If you begin with 10. liters of 0.15 M NaCl, how many grams of NaOH can be formed? (a) 60. g (b) 120 g(c) 30. g (d) 6.0 g

5-32. Diborane, B2H6, can be produced by the following reaction.

2 NaBH4(aq) + H

2SO

4(aq) → 2 H

2(g) + Na

2SO

4(aq) + B

2H

6(g)

How many milliliters of 0.0875 M H2SO4 should be used to completely consume 1.35 g ofNaBH4 (molar mass = 37.83 g/mol)? (a) 135 mL (b) 1.56 mL(c) 204 mL (d) 408 mL

5-33. Diborane, B2H6, can be produced by the following reaction.

2 NaBH4(aq) + H

2SO

4(aq) → 2 H

2(g) + Na

2SO

4(aq) + B

2H

6(g)

How many grams of B2H6 (molar mass = 27.67 g/mol) can be prepared in theory if onebegins with 250. mL of 0.0875 M H2SO4 and 1.55 g of NaBH4 (molar mass = 37.83g/mol)? (a) 0.303 g (b) 0.567 g(c) 1.13 g (d) 0.605 g

5-34. In the photographic process silver bromide is dissolved by adding sodium thiosulfate.AgBr(s) + 2 Na

2S

2O

3(aq) → Na

3Ag(S

2O

3)2(aq) + NaBr(aq)

If you want to dissolve 0.250 g of AgBr (molar mass = 187.8 g/mol), how many millilitersof 0.0138 M Na2S2O3 should you add? (a) 193 mL (b) 96.5 mL(c) 386 mL (d) 250. mL

5-35. Hydrazine, N2H4, a base like ammonia, can react with an acid such as sulfuric acid.

2 N2H

4(aq) + H

2SO

4(aq) → 2 N

2H

5+(aq) + SO

42-(aq)

How many grams of hydrazine can be consumed by 250. mL of 0.225 M H2SO4?(a) 361 g (b) 1.80 g(c) 57.7 g (d) 3.61 g

5-36. How many milliliters of 0.812 M HCl would be required to titrate 1.33 g of NaOH to theequivalence point? NaOH(aq) + HCl(aq) → NaCl(aq) + H

2O(l )

(a) 25.6 mL (b) 41.0 mL(c) 34.2 mL (d) 20.7 mL



5-37. Acid-base titrations are an important method of chemical analysis. If you use 32.45 mL ofHCl to titrate 2.050 g of Na2CO3 (M = 105.989 g/mol) according to the equation

Na2CO

3(aq) + 2 HCl(aq) → 2 NaCl(aq) + CO

2(g) + H

2O(l )

what is the molarity of the HCl?(a) 0.00119 M (b) 2.384 M(c) 1.192 M (d) 0.596 M

5-38. How many milliliters of 0.955 M HCl would you need to titrate 2.152 g of Na2CO3 (M = 105.989 g/mol) to the equivalence point?Na

2CO

3(aq) + 2 HCl(aq) → 2 NaCl(aq) + CO

2(g) + H

2O(l)

(a) 21.3 mL (b) 34.5 mL(c) 42.5 mL (d) 85.0 mL

5-39. Potassium acid phthalate, KHC8H4O4 (molar mass = 204.22 g/mol), is used to standardizesolutions of the bases. The acidic anion reacts with bases according to the following netionic equation:HC

8H

4O

4-(aq) + OH-(aq) → H

2O(l) + C

8H

4O

42-(aq)

If a 0.902 g sample of potassium acid phthalate is dissolved in water and titrated to theequivalence point with 26.45 mL of NaOH, what is the molarity of the NaOH?(a) 0.0835 M (b) 0.125 M(c) 0.167 M (d) 0.599 M

5-40. A soft drink contains an unknown amount of citric acid, C6H8O7. If 100. mL of the softdrink require 33.51 mL of 0.0102 M NaOH to neutralize completely the citric acid, howmany grams of citric acid (molar mass = 192.13 g/mol) does the soft drink contain per 100mL? The reaction of citric acid and NaOH is C

6H

8O

7(aq) + 3 NaOH(aq) → Na

3C

6H

5O

7(aq) + 3 H

2O(l)

(a) 0.0219 g (b) 0.220 g(c) 0.0666 g (d) 0.657 g

5-41. You are given a 4.554 g of a mixture of oxalic acid, H2C2O4, and sodium chloride. If29.58 mL of 0.550 M NaOH are required to titrate the 4.554-g sample to the equivalencepoint, what is the weight percent of oxalic acid (molar mass = 90.04 g/mol) in the mixture?Oxalic acid and NaOH react according to the equationH

2C

2O

4(aq) + 2 NaOH(aq) → Na

2C

2O

4(aq) + 2 H

2O(l)

(a) 32.2% (b) 73.2%(c) 16.1% (d) 8.85%



5-42. Sodium thiosulfate, Na2S2O3, is used as a “fixer” in black and white photography. Assume you have a bottle of sodium thiosulfate and want to determine its purity. You cantitrate the thiosulfate ion with I2 according to the equation

I2(aq) + 2 S

2O

32-(aq) → 2 I-(aq) + S

4O

62-(aq)

If you use 40.21 mL of 0.246 M I2 in the titration, what is the weight percent of Na2S2O3(molar mass = 158.12 g/mol) in a 3.232-g sample of impure Na2S2O3?(a) 24.2% (b) 48.4%(c) 96.8% (d) 100.0%

5-43. The lead content of a sample can be estimated by converting the lead to PbO2

Pb in sample + oxidizing agent → PbO2(s)

and then dissolving the PbO2 (M = 239.20 g/mol) in an acid solution of KI. This liberatesI2 according to the equation

PbO2(s) + 4 H+(aq) + 2 I-(aq) → Pb2+(aq) + I

2(aq) + 2 H

2O(l)

The liberated I2 is then titrated with Na2S2O3.

I2(aq) + 2 S

2O

32-(aq) → 2 I-(aq) + S

4O

62-(aq)

The amount of titrated I2 is related to the amount of lead in the sample. If 0.576 g of lead-containing mineral requires 35.23 mL of 0.0500 M Na2S2O3 for titration of the liberatedI2, calculate the weight percent of lead in the mineral. (a) 95.0% (b) 63.4%(c) 15.8% (d) 31.7%

5-44. You are given an acid and told only that it could be citric acid (molar mass = 192.1 g/mol)or tartaric acid (molar mass = 150.1 g/mol). To determine which acid you have you titrateit with NaOH. The appropriate reactions are:Citric acid: C

6H

8O

7 + 3 NaOH → Na

3C

6H

5O

7 + 3 H

2O

Tartaric acid: C4H

6O

6 + 2 NaOH → Na

2C

4H

4O

6 + 2 H

2O

To determine which acid you have you titrate 0.956 g with 29.1 mL of 0.513 M NaOH. Which acid do you have?(a) citric acid (b) tartaric acid

5-45. Cobalt(III) ion forms many compounds with ammonia. To find the formula of one of thesecompounds, you titrate the NH3 with standardized acid (HCl).

Co(NH3)xCl

3(aq) + x HCl(aq) → x NH

4+(aq) + Co3+(aq) + (x + 3) Cl-(aq)

Assume you use 23.63 mL of 1.500 M HCl to titrate 1.580 g of Co(NH3)xCl3. What isthe value of x?(a) 2 (b) 3(c) 4 (d) 6



5-46. Give the oxidation number for the underlined atom in each of the compounds below.(i) H2S _____ (iv) C6H6 _____

(ii) H2SO4 _____ (v) CrO2- _____

(iii) HClO _____ (vi) H4P2O7 _____

5-47. Aluminum reacts with bromine according to the following balanced, oxidation-reductionequation: 2 Al(s) + 3 Br

2(l) → Al

2Br

6(s). Which answer correctly describes the

reaction?(a) Al is the oxidizing agent and Br2 is the reducing agent.(b) Al is oxidized and Br2 is reduced.

(c) Br2 is reduced to Br3- and Al is oxidized to Al+.(d) none of the above

5-48. Many metals react readily with acids to give a metal-containing salt and H2 gas.

Ca(s) + 2 HCl(aq) → CaCl2(aq) + H

2(g)

Which answer correctly describes the reaction above?(a) Ca is the oxidizing agent and HCl is the reducing agent.(b) HCl is oxidized and Ca is reduced.(c) Ca is the reducing agent and HCl is reduced.(d) None of the above

5-49. Iodide ion reacts with manganese(IV) oxide according to the following balanced, oxidation-reduction equation:MnO

2(s) + 2 I-(aq) + 4 H+(aq) → I

2(aq) + Mn2+(aq) + 2 H

2O(l)

Which answer correctly describes the reaction?(a) Mn in MnO2 is reduced to Mn2+ and I- is oxidized to I2.

(b) I- is reduced to I2 and H+ is oxidized to H2O.

(c) I- is the oxidizing agent and MnO2 is the reducing agent.

(d) H+ is the oxidizing agent, and I- is the reducing agent.

5-50. Which of the answers below is the correctly balanced half-reaction for the reduction of theVO2+ ion in acid solution?(a) VO2+(aq) + 4 H+(aq) → V3+(aq) + 2 H

2O(l) + 3 e-

(b) VO2+(aq) + H+(aq) → V3+(aq) + H2O(l ) + e-

(c) VO2+(aq) + 2 H+(aq) + e- → V3+(aq) + H2O(l)

(d) VO2+(aq) + 2 H+(aq) → V3+(aq) + H2O(l) + e-



5-51. Which of the answers below is the correctly balanced half-reaction for the reduction of theSO4

2- ion in acid solution?

(a) SO4

2-(aq) + 2 H+(aq) → H2SO

3(aq) + H

2O(l)

(b) SO4

2-(aq) + 4 H+(aq) → H2SO

3(aq) + H

2O(l) + 2 e-

(c) SO4

2-(aq) + 4 H+(aq) + 2 e- → H2SO

3(aq) + H

2O(l)

(d) SO4

2-(aq) + 4 H+(aq) + 4 e- → H2SO

3(aq) + H

2O(l)

5-52. Which of the answers below is the correctly balanced half-reaction for the oxidation ofethyl alcohol to acetic acid in acid solution?(a) CH

3CH

2OH(aq) + H

2O(l) → CH

3COOH(aq) + 4 H+(aq) + 4 e-

(b) CH3CH

2OH(aq) + 2 H

2O(l) + 2 e- → CH

3COOH(aq) + 2 H+(aq)

(c) CH3CH

2OH(aq) + 1/2 O

2(g) → CH

3COOH(aq) + 2 H+(aq) + 2 e-

(d) CH3CH

2OH(aq) + 2 H

2O(l) → CH

3COOH(aq) + 2 H+(aq) + 2 e-

5-53. Which of the following represents a balanced, overall equation for the oxidation of zinc innitric acid solution?Zn(s) + NO

3-(aq) → Zn2+(aq) + N

2O(g)

(a) Zn(s) + 2 NO3

-(aq) + 2 H+(aq) → Zn2+(aq) + N2O(g) + H

2O(l)

(b) 4 Zn(s) + 2 NO3

-(aq) + 2 H+(aq) → 4 Zn2+(aq) + N2O(g) + H

2O(l)

(c) Zn(s) + 2 NO3

-(aq) → Zn2+(aq) + N2O(g) + 5 H

2O(l)

(d) 4 Zn(s) + 2 NO3

-(aq) + 10 H+(aq) → 4 Zn2+(aq) + N2O(g) + 5 H

2O(l)

5-54. Which of the following represents a balanced, overall equation for the reduction of silver inacid solution?Ag+(aq) + HCHO(aq) → Ag(s) + HCOOH(aq)

(a) Ag+(aq) + HCHO(aq) → Ag(s) + HCOOH(aq)

(b) Ag+(aq) + HCHO(aq) + e- → Ag(s) + HCOOH(aq)

(c) 2 Ag+(aq) + HCHO(aq) + H2O(l) → 2 Ag(s) + HCOOH(aq) + 2 H+(aq)

(d) Ag+(aq) + HCHO(aq) + 1/2 O2(g) → Ag(s) + HCOOH(aq)

5-55. Which of the following represents a balanced, overall equation for the reduction ofoxidation of vitamin C (C6H8O6) with bromine in acid solution?

(a) Br2(aq) + C

6H

8O

6(aq) → 2 Br-(aq) + C

6H

6O

6(aq)

(b) Br2(aq) + C

6H

8O

6(aq) → 2 Br-(aq) + C

6H

6O

6(aq) + 2 H+(aq)

(c) Br2(aq) + C

6H

8O

6(aq) + H

2O(l) → 2 Br-(aq) + C

6H

6O

6(aq) + 2 H+(aq)

(d) Br2(aq) + C

6H

8O

6(aq) → Br

-(aq) + C

6H

6O

6(aq) + 2 H

+(aq)



5-56. Which of the following represents a balanced, overall equation for the oxidation of iron(II)in acid solution?Cr

2O

72-(aq) + Fe2+(aq) → 2 Cr3+(aq) + Fe3+(aq)

(a) Cr2O

72-(aq) + 6 Fe2+(aq) + 14 H+(aq) → 2 Cr3+(aq) + 6 Fe3+(aq) + 7 H

2O(l)

(b) Cr2O

72-(aq) + 6 Fe2+(aq) + 7 H+(aq) → 2 Cr3+(aq) + 6 Fe3+(aq) + 7 H

2O(l)

(c) Cr2O

72-(aq) + 6 Fe2+(aq) + 14 H+(aq) → Cr3+(aq) + 6 Fe3+(aq) + 7 H

2O(l)

(d) Cr2O

72-(aq) + Fe2+(aq) + 14 H+(aq) → 2 Cr3+(aq) + Fe3+(aq) + 7 H

2O(l)

5-57. Aqueous Co2+ can be oxidized with hypochlorite ion in basic solution according to thefollowing reaction.2 Co2+(aq) + OCl-(aq) + 4 OH-(aq) + H

2O(aq) → 2 Co(OH)

3(s) + Cl-(aq)

(i) The hypochlorite ion functions as the (a) oxidizing agent (b) reducing agent

(ii) The balanced half-reaction for the hypochlorite ion in this reaction is(a) OCl-(aq) + OH-(aq) + H

2O(aq) → Cl-(aq) + e-

(b) OCl-(aq) + e- + H2O(aq) → Cl-(aq) + OH- (aq)

(c) OCl-(aq) + 2 e- + H2O(aq) → Cl-(aq) + 2 OH-(aq)

(d) none of the above

5-58. The following is the balanced net ionic equation for an oxidation-reduction reaction.MnO

2(s) + 2 I-(aq) + 4 H+(aq) → I

2(aq) + Mn2+(aq) + 2 H

2O(l)

If you use 1.234 g of MnO2 (molar mass = 86.937 g/mol), how many milliliters of 0.730M NaI solution are required for complete reaction?(a) 5.2 mL (b) 19.5 mL(c) 25.7 mL (d) 38.9 mL

5-59. For each reaction below, tell if it is best described as (a) an oxidation-reduction reaction(b) a simple exchange reaction(c) an acid-base reaction

Reaction Type Equation(i) _____________ CuCl

2 + 2 Ag → Cu + 2 AgCl

(ii) _____________ 2 NaOH + H2SO

4 → Na

2SO

4 + 2 H

2O

(iii) _____________ CuCl2 + Na

2S → 2 NaCl + CuS



5-60. You want to prepare a sample of copper(II) chloride. To do this, you have the followingreagents to select from:CuCO3 CuSO4 CuBr2 KCl H2SO4 HCl AgNO3 Cu(OH)2 BaCl2 Which pair of reagents below is not appropriate to use?(a) CuCO3, HCl (b) Cu(OH)2, HCl(c) CuSO4, BaCl2 (d) CuSO4, KCl

5-61. Nickel(II) chloride can be made by an exchange reaction between the metal carbonate andan acid.NiCO

3(s) + 2 HCl(aq) → NiCl

2(aq) + CO

2(g) + H

2O(l)

If you begin with 2.37 g of NiCO3 (M = 118.7 g/mol) and 500. mL of 0.125 M HCl, what is the theoretical yield of NiCl2?(a) 1.14 g (b) 2.59 g(c) 4.05 g (d) 4.56 g

5-62. The following redox reaction occurs in acid solution: 3 C

6H

8O

6(aq) + BrO

3-(aq) → Br-(aq) + 3 C

6H

6O

6(aq) + 3 H

2O(l)

How many milliliters of 0.108 M BrO3- would you need to completely consume 125 mL of

0.0525 M C6H8O6? (a) 10.1 mL (b) 20.3 mL(c) 40.5 mL (d) 60.8 mL

5-63. You are given 0.954 g of an unknown acid, H2A. You know that it reacts with NaOHaccording to the balanced equation

H2A(aq) + 2 NaOH(aq) → Na

2A(aq) + 2 H

2O(l)

You use 36.04 mL of 0.509 M NaOH to titrate the acid to the equivalence point. What isthe molar mass of the acid?(a) 52.0 g/mol (b) 104 g/mol(c) 126 g/mol (d) 208 g/mol

5-64. You are given a sample of a copper-containing alloy and asked to determine the weightpercent of copper. After dissolving the metal in acid, you add an excess of KI, and theCu2+ and I- ions undergo the reaction

2 Cu2+(aq) + 5 I-(aq) → 2 CuI(s) + I3

-(aq)

The liberated I3- is titrated with sodium thiosulfate according to the equation

I3

-(aq) + 2 S2O

32-(aq) → S

4O

62-(aq) + 3 I-(aq)

If 26.32 mL of 0.101 M Na2S2O3 is required for titration to the equivalence point, what isthe weight percent of Cu in 0.251 g of the alloy?(a) 74.3% (b) 67.2%(c) 93.4% (d) 33.6%



5-65. The following oxidation-reduction reaction occurs in acid solution:5 U4+(aq) + MnO

4-(aq) + 6 H

2O(l) → 5 UO

2+(aq) + Mn2+(aq) + 12 H+(aq)

(i) The oxidation number of U in UO2+ is _______ and of Mn in MnO4

- is ________.(ii) The reducing agent is ____________ and the substance reduced is ____________.(iii) How many milliliters of 0.216 M KMnO4 are required to react with 11.6 g of UF4

(the source of the U4+ ion) (M = 314.0 g/mol)?(a) 34.2 mL (b) 3.42 mL(c) 171 mL (d) 6.84 mL

ANSWERS — CHAPTER 51. b 11. c 21. b2. c 12. c 22. c3. c 13. b 23. a4. d 14. a 24. b5. a 15. b 25. c6. b 16. c 26. d7. d 17. a 27. b8. c 18. c 28. a9. c 19. d 29. c10. b 20. a 30. d

31. a 41. c 51 c32. c 42. c 52. a33. b 43. d 53. d34. a 44. a 54. c35. d 45. d 55. b36. b 46. i = -2, ii = +6, iii = +1 56. a

iv = -1, v = +3, vi = +537. c 47. b 57. i = a, ii = c38. c 48. c 58. d39. c 49. a 59. i = a, ii = c,

iii = b40. a 50. c 60. d

61. b62. b63. b64. b65. i = +5, +7; ii = U4+, MnO4

-; iii = a


(Eonta) Reactions on Aqueous Reactions

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