Interpretation Introduction Introduction: From the stoichiometry of the equation, the equivalence point occurs when the amount (in moles) of added base is equal to the amount (in moles) of acid initially in the solution. Explanation The reaction in titration is as follows: N a O H ( a q ) + H C N ( a q ) → H 2 O ( l ) + N a C N ( a q ) First, calculate the initial moles of HCN by multiplying the concentration and volume (in L): = 10.0 × 10 − 3 L × 0.200 M = 0.00200 m o l The amount of N a O H that must be added is 0.00200 m o l . The volume of N a O H required is, therefore, = 0.00200 m o l o f N a O H × 1 L 0.0998 m o l o f N a O H = 0.0200 L ( o r 20.0 m L ) The equivalence point occurs when 20.0 m L of base has been added. At the equivalence point, 0.002 m o l of O H − has been added and, therefore, all HCN has been converted into its conjugate base ( C N − ) as summarized in the following table: O H − ( a q ) + H C N ( a q ) → H 2 O ( l ) + C N − ( a q ) B e f o r e a d d i t i o n ≈ 0.00 m o l 0.00200 m o l − 0.00 m o l A d d i t i o n 0.00200 m o l − − − A f t e r a d d i t i o n ≈ 0.00 m o l 0.00 m o l − 0.00200 m o l The solution is no longer a buffer (it no longer contains significant amounts of both a weak acid and its conjugate base). Instead, the solution contains an ion ( C N − ) acting as a weak base. Calculate the p H by working on equilibrium problem for the ionization of water by the ion ( C N − ) acting as a weak base. C N − ( a q ) + H 2 O ( l ) ⇌ H C N ( a q ) + O H − ( a q ) ⇋ C N − ( a q ) + H 2 O ( l ) ⇌ H C N ( a q ) + O H − ( a q ) Calculate the initial concentration of C N − for the equilibrium problem by dividing the number of moles of C N − ( 0.00200 m o l ) by the total volume at the equivalence point: [ Initial v o l u m e ( 10.0 m L ) + A d d e d v o l u m e a t t h e equivalence point ] [ C N − ] = M o l e s o f C N − a t e q u i l i b r i u m point [ I n i t i a l v o l u m e ( 10.0 m L ) + A d d e d v o l u m e a t t h e e q u i v a l e n c e point ] = 0.00200 m o l 10.0 m L + 20.0 m L = 0.00200 m o l 30.0 m L × 1 L 1000 m L ( 1 L = 1000 m L ) = 0.0667 mol/L Therefore, the concentration of C N − i s 0.0667 mol/L . Solve the equilibrium as follows: C N − ( a q ) + H 2 O ( l ) ⇌ H C N ( a q ) + O H − ( a q ) [ C N − ] [ H C N ] [ O H − ] I n i t i a l 0

3rd Edition

ISBN: 9780321809247

Author: Nivaldo J. Tro

Publisher: Prentice Hall

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Acid Base Titration

An acid-base titration is the method of quantitative analysis for determining the concentration of an acid and base by exactly neutralizing it with a standard solution of base or acid having known concentration.

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Chapter 16, Problem 8SAQ

Interpretation Introduction

Introduction: From the stoichiometry of the equation, the equivalence point occurs when the amount (in moles) of added base is equal to the amount (in moles) of acid initially in the solution.

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Chapter 16, Problem 7SAQ

Chapter 16, Problem 9SAQ

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Chapter 16 Solutions

Chemistry: A Molecular Approach

Ch. 16 - Prob. 1SAQ Ch. 16 - Q2. What is the pH of a buffer that is 0.120 M in...Ch. 16 - Q3. A buffer with a pH of 9.85 contains CH3NH2 and...Ch. 16 - Q4. A 500.0-mL buffer solution is 0.10 M in...Ch. 16 - Q5. Consider a buffer composed of the weak acid HA...Ch. 16 - Q6. Which combination is the best choice to...Ch. 16 - Q7. A 25.0-mL sample of an unknown HBr solution is...Ch. 16 - Q8. A 10.0-mL sample of 0.200 M hydrocyanic acid...Ch. 16 - Q9. A 20.0-mL sample of 0.150 M ethylamine is...Ch. 16 - Q10. Three 15.0-mL acid samples—0.10 M HA, 0.10 M...

Ch. 16 - Q11. A weak unknown monoprotic acid is titrated...Ch. 16 - Q12. Calculate the molar solubility of lead(II)...Ch. 16 - Q13. Calculate the molar solubility of magnesium...Ch. 16 - Q14. A solution is 0.025 M in Pb2 +. What minimum...Ch. 16 - Q15. Which compound is more soluble in an acidic...Ch. 16 - 1. What is the pH range of human blood? How is...Ch. 16 - 2. What is a buffer? How does a buffer work? How...Ch. 16 - 3. What is the common ion effect? Ch. 16 - 4. What is the Henderson–Hasselbalch equation, and...Ch. 16 - 5. What is the pH of a buffer solution when the...Ch. 16 - 6. Suppose that a buffer contains equal amounts of...Ch. 16 - 7. How do you use the Henderson–Hasselbalch...Ch. 16 - 8. What factors influence the effectiveness of a...Ch. 16 - 9. What is the effective pH range of a buffer...Ch. 16 - 10. Describe acid–base titration. What is the...Ch. 16 - 11. The pH at the equivalence point of the...Ch. 16 - 12. The volume required to reach the equivalence...Ch. 16 - 13. In the titration of a strong acid with a...Ch. 16 - 14. In the titration of a weak acid with a strong...Ch. 16 - 15. The titration of a polyprotic acid with...Ch. 16 - 16. In the titration of a polyprotic acid, the...Ch. 16 - 17. What is the difference between the endpoint...Ch. 16 - 18. What is an indicator? How can an indicator...Ch. 16 - 19. What is the solubility product constant? Write...Ch. 16 - 20. What is molar solubility? How can you obtain...Ch. 16 - 21. How does a common ion affect the solubility of...Ch. 16 - 22. How is the solubility of an ionic compound...Ch. 16 - 23. For a given solution containing an ionic...Ch. 16 - 24. What is selective precipitation? Under which...Ch. 16 - 25. What is qualitative analysis? How does...Ch. 16 - 26. What are the main groups in the general...Ch. 16 - 27. In which of these solutions will HNO2 ionize...Ch. 16 - 28. A formic acid solution has a pH of 3.25. Which...Ch. 16 - 29. Solve an equilibrium problem (using an ICE...Ch. 16 - 30. Solve an equilibrium problem (using an ICE...Ch. 16 - 31. Calculate the percent ionization of a 0.15 M...Ch. 16 - 32. Calculate the percent ionization of a 0.13 M...Ch. 16 - 33. Solve an equilibrium problem (using an ICE...Ch. 16 - 34. Solve an equilibrium problem (using an ICE...Ch. 16 - 35. A buffer contains significant amounts of...Ch. 16 - 36. A buffer contains significant amounts of...Ch. 16 - Prob. 37E Ch. 16 - Prob. 38E Ch. 16 - 39. Use the Henderson–Hasselbalch equation to...Ch. 16 - 40. Use the Henderson–Hasselbalch equation to...Ch. 16 - 41. Calculate the pH of the solution that results...Ch. 16 - 42. Calculate the pH of the solution that results...Ch. 16 - 43. Calculate the ratio of NaF to HF required to...Ch. 16 - 44. Calculate the ratio of CH3NH2 to CH3NH3Cl...Ch. 16 - Prob. 45E Ch. 16 - 46. What mass of ammonium chloride should you add...Ch. 16 - 47. A 250.0-mL buffer solution is 0.250 M in...Ch. 16 - 48. A 100.0-mL buffer solution is 0.175 M in HClO...Ch. 16 - Prob. 49E Ch. 16 - 50. For each solution, calculate the initial and...Ch. 16 - Prob. 51E Ch. 16 - 52. A 100.0-mL buffer solution is 0.100 M in NH3...Ch. 16 - 53. Determine whether or not the mixing of each...Ch. 16 - 54. Determine whether or not the mixing of each...Ch. 16 - 55. Blood is buffered by carbonic acid and the...Ch. 16 - 56. The fluids within cells are buffered by H2PO4–...Ch. 16 - 57. Which buffer system is the best choice to...Ch. 16 - Prob. 58E Ch. 16 - 59. A 500.0-mL buffer solution is 0.100 M in HNO2...Ch. 16 - Prob. 60E Ch. 16 - Prob. 61E Ch. 16 - 62. Two 25.0-mL samples, one 0.100 M HCl and the...Ch. 16 - 63. Two 20.0-mL samples, one 0.200 M KOH and the...Ch. 16 - 64. The graphs labeled (a) and (b) show the...Ch. 16 - 65. Consider the curve shown here for the...Ch. 16 - 66. Consider the curve shown here for the...Ch. 16 - 67. Consider the titration of a 35.0-mL sample of...Ch. 16 - Prob. 68E Ch. 16 - 69. Consider the titration of a 25.0-mL sample of...Ch. 16 - Prob. 70E Ch. 16 - 71. Consider the titration of a 20.0-mL sample of...Ch. 16 - Prob. 72E Ch. 16 - Prob. 73E Ch. 16 - Prob. 74E Ch. 16 - Consider the titration curves (labeled a and b)...Ch. 16 - Prob. 76E Ch. 16 - Prob. 77E Ch. 16 - 78. A 0.446-g sample of an unknown monoprotic acid...Ch. 16 - Prob. 79E Ch. 16 - Prob. 80E Ch. 16 - Prob. 81E Ch. 16 - Prob. 82E Ch. 16 - Prob. 83E Ch. 16 - 84. Referring to Table 17.1, pick an indicator for...Ch. 16 - Prob. 85E Ch. 16 - Prob. 86E Ch. 16 - 87. Refer to the Ksp values in Table 17.2 to...Ch. 16 - 88. Refer to the Ksp values in Table 17.2 to...Ch. 16 - 89. Use the given molar solubilities in pure water...Ch. 16 - Prob. 90E Ch. 16 - Prob. 91E Ch. 16 - Prob. 92E Ch. 16 - 93. Refer to the Ksp value from Table 17.2 to...Ch. 16 - Prob. 94E Ch. 16 - 95. Calculate the molar solubility of barium...Ch. 16 - Prob. 96E Ch. 16 - Prob. 97E Ch. 16 - Prob. 98E Ch. 16 - Prob. 99E Ch. 16 - Prob. 100E Ch. 16 - Prob. 101E Ch. 16 - Prob. 102E Ch. 16 - Prob. 103E Ch. 16 - Prob. 104E Ch. 16 - Prob. 105E Ch. 16 - Prob. 106E Ch. 16 - Prob. 107E Ch. 16 - Prob. 108E Ch. 16 - Prob. 109E Ch. 16 - Prob. 110E Ch. 16 - Prob. 111E Ch. 16 - Prob. 112E Ch. 16 - 113. A 150.0-mL solution contains 2.05 g of sodium...Ch. 16 - Prob. 114E Ch. 16 - Prob. 115E Ch. 16 - Prob. 116E Ch. 16 - Prob. 117E Ch. 16 - 118. A 250.0-mL buffer solution initially contains...Ch. 16 - 119. In analytical chemistry, bases used for...Ch. 16 - Prob. 120E Ch. 16 - Prob. 121E Ch. 16 - Prob. 122E Ch. 16 - Prob. 123E Ch. 16 - Prob. 124E Ch. 16 - Prob. 125E Ch. 16 - Prob. 126E Ch. 16 - Prob. 127E Ch. 16 - Prob. 128E Ch. 16 - Prob. 129E Ch. 16 - Prob. 130E Ch. 16 - 131. The Kb of hydroxylamine, NH2OH, is 1.10 ×...Ch. 16 - 132. A 0.867-g sample of an unknown acid requires...Ch. 16 - Prob. 133E Ch. 16 - Prob. 134E Ch. 16 - 135. What relative masses of dimethyl amine and...Ch. 16 - Prob. 136E Ch. 16 - Prob. 137E Ch. 16 - Prob. 138E Ch. 16 - 139. Since soap and detergent action is hindered...Ch. 16 - 140. A 0.558-g sample of a diprotic acid with a...Ch. 16 - 141. When excess solid Mg(OH)2 is shaken with 1.00...Ch. 16 - Prob. 142E Ch. 16 - Prob. 143E Ch. 16 - Prob. 144E Ch. 16 - Prob. 145E Ch. 16 - Prob. 146E Ch. 16 - Prob. 147E Ch. 16 - 148. What amount of HCl gas must be added to 1.00...Ch. 16 - 149. Without doing any calculations, determine if...Ch. 16 - 150. A buffer contains 0.10 mol of a weak acid and...Ch. 16 - Prob. 151E Ch. 16 - Prob. 152E Ch. 16 - Prob. 153E

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