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1 | |
What is the pH of a sodium formate/formic acid buffer solution containing equal concentrations of both buffer components? [Ka formic acid = 1.7 x 10-4] |
| | A) | 7.0 |
| | B) | 6.2 |
| | C) | 3.8 |
| | D) | 3.0 |
| | E) | We cannot determine the pH of the buffer solution unless we know the actual concentrations of the buffer components |
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2 | |
A buffer solution is prepared by dissolving 0.10 mol of acetic acid and 0.10 mol of sodium acetate in 1 L of solution. A 10-mL portion of 1 M HCl is then added to the solution. How much does the addition change the pH of the buffer? [Ka(CH3COOH) = 1.8 x 10-5] |
| | A) | 0.88 pH units |
| | B) | 0.12 pH units |
| | C) | 1.2 pH units |
| | D) | 0.087 pH units |
| | E) | 0.82 pH units |
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3 | |
Which of the following combinations, when dissolved in equimolar amounts in water, would produce a buffer solution? |
| | A) | NaCl and NaC2H3O2 |
| | B) | HC2H3O2 and NaCl |
| | C) | HNO3 and NaOH |
| | D) | NaNO3 and NH3 |
| | E) | NH3 and NH4Cl |
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4 | |
When an acid, HA, is titrated with 0.1 M NaOH, the pH at the half equivalence point of the titration is 4.5. What is the Ka of the acid? |
| | A) | 3.2 x 10-5 |
| | B) | 3.2 x 10-10 |
| | C) | 1.8 x 10-3 |
| | D) | 7.0 x 10-7 |
| | E) | HA is a strong acid |
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5 | |
Methyl red is a commonly used acid-base indicator with a Ka of 6.3 x 10-6. The unionized form of methyl red (HIn) is red, and the ionized form (In-) is yellow. What color would a 1.0 x 10-2 M aqueous solution of methyl red have at pH = 4? |
| | A) | colorless |
| | B) | yellow |
| | C) | red |
| | D) | There's really no way to tell without preparing the solution and checking its color. |
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6 | |
The solubility of AlF3 is 6.7 g AlF3 per liter of solution. The density of a saturated AlF3 solution is 1.0 g/mL. The Ksp of AlF3 is: |
| | A) | 1.9 x 10-2 |
| | B) | 6.0 x 10-3 |
| | C) | 1.1 x 10-3 |
| | D) | 4.0 x 10-4 |
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7 | |
Calculate the concentration of calcium ions present in a saturated calcium phosphate solution. [Ksp Ca3(PO4)2 = 1.3 x 10-26] |
| | A) | 1.2 x 10-5 M |
| | B) | 2.0 x 10-5 M |
| | C) | 2.6 x 10-6 M |
| | D) | 7.8 x 10-6 M |
| | E) | 8.3 x 10-6 M |
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8 | |
The Ksp of PbI2 is 1.4 x 10-8. Calculate the molar solubility of PbI2 in 0.01 M NaI. |
| | A) | 1.5 x 10-3 M |
| | B) | 1.4 x 10-4 M |
| | C) | 1.4 x 10-6 M |
| | D) | 5.6 x 10-2 M |
| | E) | None of the above. |
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9 | |
Which of the following compounds is appreciably more soluble in 1 M HNO3 than in pure water? |
| | A) | FeCO3 |
| | B) | AgBr |
| | C) | BaSO4 |
| | D) | NaNO3 |
| | E) | NaCl |
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10 | |
Silver chloride is insoluble in water, but soluble in NH3 solution because NH3 |
| | A) | raises the solution pH, and AgCl dissolves in basic solutions. |
| | B) | lowers the solution pH, and AgCl is soluble in acidic solutions. |
| | C) | complexes Cl-, shifting the equilibrium and allowing AgCl to dissolve. |
| | D) | complexes Ag+, shifting the equilibrium and allowing AgCl to dissolve. |
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2002 McGraw-Hill Higher Education