Gen Chem II Exam 4 titration, ksp practice problems f08

Gen Chem II Exam 4 titration, ksp practice problems f08 - 1...

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1 CH302 Exam 4 Practice Problems (buffers, titrations, Ksp) Equilibrium Constants The following equilibrium constants will be useful for some of the problems. Substance Constant Substance Constant HCO 2 H K a = 1.8 × 10 -4 H 2 CO 3 K 1 = 4.2 × 10 -7 HNO 2 K a = 4.5 × 10 -4 K 2 = 4.8 × 10 -11 HOCl K a = 3.5 × 10 -8 (COOH) 2 K 1 = 5.9 × 10 -2 HF K a = 7.2 × 10 -4 K 2 = 6.4 × 10 -5 HCN K a = 4.0 × 10 -10 CH 3 COOH K a = 1.8 × 10 -5 H 2 SO 4 K 1 = very large C 6 H 5 NH 2 K b = 4.2 × 10 -10 K 2 = 1.2 × 10 -2 NH 3 K b = 1.8 × 10 -5 HOBr K a = 2.5 × 10 -9 1.Refer to Equilibrium Constants. The nonionized form of an acid indicator is yellow, and its anion is blue. The K a of this indicator is 10 -6 . What will be the approximate pH range over which this indicator changes color? a. 3-5 d. 8-10 b. 4-6 e. 9-11 c. 5-7 2.Refer to Equilibrium Constants. The equivalence point of the titration of an unknown base with HCl is at pH = 5.90. What would be the K a for the best choice of an indicator for this titration? a. 10 -2 d. 10 -6 b. 10 -4 e. 10 -7 c. 10 -8 3.Refer to Equilibrium Constants. What is the pH at the point in a titration at which 20.00 mL of 1.000 M KOH has been added to 25.00 mL of 1.000 M HBr? a. 1.67 d. 2.71 b. 0.95 e. 1.22 c. 3.84 4.Refer to Equilibrium Constants. Which titration curve could describe the titration of a solution of HCl by addition of a solution of KOH? a. b. c.
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2 d. e. 5.Refer to Equilibrium Constants. Which indicator could be used to titrate aqueous NH 3 with HCl solution? Acid Range Color pH Range Basic Range Color a. pink 1.2-2.8 yellow b. blue 3.4-4.6 yellow c. yellow 6.5-7.8 purple d. colorless 8.3-9.9 red e. none of these indicators
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Gen Chem II Exam 4 titration, ksp practice problems f08 - 1...

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