Q&A Hero

Q: Formic acid (HCO2H, Ka = 1.8 10-4) is the principal component in the venom of stinging ants. What is the molarity of a formic acid solution if 25.00 mL of the formic acid solution requires 29.80 mL of 0.0567 M NaOH to reach the equivalence point? A) 0.0134 M B) 0.0476 M C) 0.0567 M D) 0.0676 M

Q: What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous hydrofluoric acid requires 30.00 mL of 0.400 M NaOH? Ka = 6.76 10-4 for HF. A) 1.74 B) 5.75 C) 8.25 D) 12.26

Q: What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous formic acid requires 29.80 mL of 0.3567 M NaOH? Ka =1.8 10-4 for formic acid.A) 2. 06B) 5. 48C) 8. 52D) 11.94

Q: What is the pH of a solution made by mixing 25.00 mL of 0. 100 M HCl with 40.00 mL of 0.100 M KOH? Assume that the volumes of the solutions are additive. A) 0.64 B) 1.64 C) 12.36 D) 13.36

Q: What volume of 5.00 10-3 M HNO3 is needed to titrate 80.00 mL of 5.00 10-3 M Ca(OH)2 to the equivalence point?A) 10.0 mLB) 40.0 mLC) 80.0 mLD) 160. mL

Q: What is the [CH3CO2-]/[CH3CO2H] ratio necessary to make a buffer solution with a pH of 4.34? Ka = 1.8 10-5 for CH3CO2H. A) 0. 39:1 B) 0. 91:1 C) 1. 09:1 D) 2.5:1

Q: What is the pH of a buffer system prepared by dissolving 10.70 grams of NH4Cl and 25.00 mL of 12 M NH3 in enough water to make 1.000 L of solution? Kb = 1.80 10-5 for NH3. A) 9.08 B) 9.26 C) 9. 43 D) 11. 32

Q: What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M methylamine, CH3NH2, with 20.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of the solutions are additive and that Kb = 3.70 10-4 for methylamine. A) 10.17 B) 10.57 C) 10.97 D) 11.78

Q: What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M NH3 with 5.00 mL of 0.10 M NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 10-5 for NH3. A) 8. 25 B) 10.26 C) 10.25 D) 11.13

Q: What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.0 10 M CH3CO2Na? Assume that the volume of the solutions are additive and that Ka = 1.8 10-5 for CH3CO2H. A) 2.87 B) 3.74 C) 4.7 5 D) 5. 74

Q: What is the hydronium ion concentration in a solution prepared by mixing 50.00 mL of 0.10 M HCN with 50.00 mL of 0.030 M NaCN? Assume that the volumes of the solutions are additive and that Ka = 4.9 10-10 for HCN. A) 1.5 10- 10 M B) 4.9 10-10 M C) 1.6 10- 9 M D) 7.0 10-6 M

Q: If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of K2CO3 is added and equilibrium is restored?A) (1)B) (2)C) (3)D) (4)

Q: If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of Ca(NO3)2 is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of CaCO3, which of solutions (1)-(4) represents the solution after a small amount of NaOH is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of NH3 is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of AgNO3 is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HNO3 is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of AgCl, which of solutions (1)-(4) represents the solution after a small amount of HCl is added and equilibrium is restored? A) (1) B) (2) C) (3) D) (4)

Q: If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are supersaturated? A) (2) B) (3) C) (4) D) None of these

Q: If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are saturated? A) (2) B) (3) C) (4) D) None of these

Q: If solution (1) is a saturated solution of CuS, which of solutions (2)-(4) are unsaturated? A) only (2) B) only (3) C) only (4) D) (3) and (4)

Q: The following plot shows a titration curve for the titration of 1.00 L of 1.00 M diprotic acid H2A+ with NaOH. Which point a-d represents the isoelectric point? A) point a B) point b C) point c D) point d

Q: What is the pH at the first equivalence point? A) pH = pKa1 B) pH = 14 - pKa1 C) pH = (pKa1 + pKa2)/2 D) pH = pKa1 + pKa2

Q: Which point a-d represents pKa2? A) point a B) point b C) point c D) point d

Q: Which point a-d represents pKa1? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the second equivalence point? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the first equivalence point? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the H2X/HX- buffer region? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the HX-/X2- buffer region? A) point a B) point b C) point c D) point d

Q: A buffer region is indicated by which point(s) a-d? A) point a B) points a and c C) point b D) points b and d

Q: Which point a-d represents a buffer region? A) point a B) point b C) point c D) point d

Q: Which points a-d represent the half-equivalence point and the equivalence point, respectively, for the titration of a weak acid? A) points a and b B) points a and c C) points b and d D) points c and d

Q: At which point a-d is the pKa of the acid equal to the pH? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the equivalence point for the titration of a weak acid? A) point a B) point b C) point c D) point d

Q: Which point a-d represents the equivalence point for the titration of a strong acid? A) point a B) point b C) point c D) point d

Q: What is the characteristic pH-titration curve for the titration of a weak acid by a strong base? A) A B) B C) C D) D

Q: What is the characteristic pH-titrant curve for the titration of a strong base by a strong acid? A) A B) B C) C D) D

Q: What is the characteristic pH-titrant curve for the titration of a strong acid by a strong base? A) A B) B C) C D) D

Q: Which picture represents the system with the lowest pH? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the system with the highest pH? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the system beyond the second equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the system halfway between the first and second equivalence points? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the system at the first equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the system halfway to the first equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the solution after the equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the solution at the equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the solution before the equivalence point? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the solution before the addition of any KOH? A) (1) B) (2) C) (3) D) (4)

Q: Which picture represents the equilibrium state of the solution after addition of one OH- ion to the solution shown in picture (1)? A) (2) B) (3) C) (4) D) (5)

Q: Which picture represents the equilibrium state of the solution after addition of one H3O+ ion to the solution shown in picture (1)? A) (2) B) (3) C) (4) D) (5)

Q: For which of these solutions is pH = pKa? A) All have pH = pKa. B) (1), (2) and (3) C) (1) and (4) D) (2) and (3)

Q: Which solution has the greatest buffer capacity? A) (1) B) (2) C) (3) D) (4)

Q: Which of these solutions are buffers? A) (1) and (2) B) (1) and (3) C) (1), (2) and (3) D) All are buffer solutions.

Q: Which solution has the largest percent dissociation of HA? A) (1) B) (2) C) (3) D) (4)

Q: Which solution has the lowest pH? A) (1) B) (2) C) (3) D) (4)

Q: Which solution has the highest pH? A) (1) B) (2) C) (3) D) (4)

Q: For which solution(s) is pH = pKa? A) only solution (1) B) only solution (2) C) only solution (3) D) solutions (1) and (3)

Q: Which solution has the greatest buffer capacity? A) (1) B) (2) C) (3) D) (4)

Q: Which of the solutions are buffer solutions? A) (1) and (2) B) (1) and (3) C) (2) and (3) D) (2) and (4)

Q: Which solution has the largest percent dissociation of HA? A) (1) B) (2) C) (3) D) (4)

Q: Which solution has the lowest pH? A) (1) B) (2) C) (3) D) (4)

Q: Which solution has the highest pH? A) (1) B) (2) C) (3) D) (4)

Q: Which pair of ions can be separated by the addition of sulfide ion? A) Ag+ and Cu2+ B) Cu2+ and Bi3+ C) Pb2+ and Ca2+ D) Ca2+ and Ba2+

Q: Which pair of ions can be separated by the addition of chloride ion? A) Ag+ and Co2+ B) Cu2+ and Bi3+ C) Pb2+ and Hg22+ D) Ca2+ and Ba2+

Q: Which set of ions precipitate as sulfides? A) Ag+, Pb2+, Mn2+ B) Pb2+, Fe2+, Ca2+ C) Co2+, Ba2+, K+ D) NH4+, Na+, K+

Q: A solution may contain the following ions Ag+, Cu2+, Mn2+, Ca2+, and Na+. No precipitate formed when 0.10 M NaCl was added but a dark colored precipitate formed when H2S was added to an acidic portion of the solution. After the removal of the solid the solution was made basic and more H2S was added and a dark precipitate again formed. Treatment of the filtrate with (NH4)2CO3 resulted in a white precipitate. If no further tests were made then what conclusions can you draw? A) possible ions present Cu2+, Mn2+, Na+ B) possible ions present Cu2+, Mn2+, Ca2+ C) possible ions present Cu2+, Mn2+, Ca2+, Na+ D) possible ions present Ag+, Cu2+, Mn2+, Ca2+, Na+

Q: A solution may contain the following ions Ag+, Cu2+, Cd2+, Mn2+, Ni2+ and Na+. A white precipitate formed when 0.10 M NaCl was added and after this was removed the solution was treated with H2S gas under acidic conditions and no precipitate formed. When the solution was made basic and again treated with H2S gas a dark colored precipitate formed. If no further tests were made then what conclusions can you draw? A) possible ions present Ag+, Mn2+, Ni2+ B) possible ions present Ag+, Mn2+, Ni2+, Na+ C) possible ions present Ag+, Cu2+, Cd2+ D) possible ions present Ag+, Cu2+, Cd2+, Na+

Q: Which metal ions can be precipitated out of solution as chlorides? A) Ag+, Hg2+, Co2+ B) Cu2+, Cd2+, Bi3+ C) Ag+, Hg22+, Pb2+ D) Na+, K+, Mg2+

Q: Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn2+, Zn2+, Pb2+ and Cu2+ and 0.10 M in H2S at a pH of 0.50? A) MnS B) CuS C) PbS, CuS D) ZnS, PbS, CuS

Q: Which metal sulfides can be precipitated from a solution that is 0.01 M in Mn2+, Zn2+, Pb2+ and Cu2+ and 0.10 M in H2S at a pH of 1.0? A) MnS B) CuS C) PbS, CuS D) ZnS, PbS, CuS

Q: 0.10 M potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2. What is the Ag+ concentration when BaCrO4 just starts to precipitate? Ksp for Ag2CrO4 and BaCrO4 are 1.1 10-12 and 1.2 10-10, respectively. A) 6.5 10-5 M B) 1.3 10-4 M C) 3.2 10-4 M D) 4.3 10-2 M

Q: Potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2. Describe what happens if the Ksp for Ag2CrO4 is 1.1 10-12 and the Ksp of BaCrO4 is 1.2 10-10. A) The BaCrO4 precipitates first out of solution. B) The Ag2CrO4 precipitates first out of solution and then BaCrO4 precipitates. C) Both BaCrO4 and Ag2CrO4 precipitate simultaneously out of solution. D) Neither BaCrO4 nor Ag2CrO4 precipitates out of solution.

Q: Precipitation of an ionic compound will occur upon mixing of desired reagents if the initial ion product is ________. A) greater than the Ksp B) equal to the pKsp C) equal to the Ksp D) less than the Ksp

Q: Which of the following reactions are not consistent with the concept of acid base amphoterism?A) Al(OH)3(s) + OH-(aq) -> Al(OH)4-(aq)B) Al(OH)3(s) + 3 H3O+(aq) -> Al3+(aq) + 6 H2O(l)C) H2O(l) + H2O(l) H3O+(aq) + OH-(aq)D) Al(OH)3(s) Al3+(aq) + 3 OH-(aq)

Q: Which of the following metal hydroxides are amphoteric? A) Al(OH)3, Zn(OH)2, Cr(OH)3, Sn(OH)2 B) Cu(OH)2, Mn(OH)2, Fe(OH)2, Fe(OH)3 C) Be(OH)2, Ca(OH)2, Ba(OH)2, Sr(OH)3 D) LiOH, NaOH, KOH, RbOH

Q: What is the molar solubility of AgCl in 0.10 M NaCN if the colorless complex ion Ag(CN)2- forms? Ksp for AgCl is 1.8 10-10 and Kf for Ag(CN)2- is A) 0.050 M B) 0.10 M C) 0.20 M D) 0.40 M

Q: What is the molar solubility of AgCl in 1.0 M K2S2O3 if the complex ion Ag(S2O3)23- forms? The Ksp for AgCl is 1.8 10-10 and the Kf for Ag(S2O3)23- is 2.9 1013. A) 0.50 M B) 1.0 M C) 1.5 M D) 2.0 M

Q: What is the molar solubility of AgCl in 0.10 M NH3? Ksp for AgCl is 1.8 10-10 and the Kf for Ag(NH3)2+ is 1.7 107. A) 1.3 10-5 M B) 5.0 10-3 M C) 5.5 10-3 M D) 5.5 10-2 M

Q: In which of the following solutions would solid PbCl2 be expected to be the least soluble at 25C? A) 0.1 M HCl B) 0.1 M NaCl C) 0.1 M CaCl2 D) 0.1 M KNO3