Name:    Practice Test 3A

Multiple Choice

1.

A buffer is prepared by adding 0.4 mol of solid NaOH to 1.0 L of 1.0 M acetic acid.  Which of the following statements is true?
 A) The pH of the solution will be equal to the pKa of the acid. B) The pH of the solution will be greater than the pKa of the acid. C) The pH of the solution will be less than the pKa of the acid. D) More information is needed to solve this problem.

2.

What is the pH of a 0.0100 M sodium benzoate solution?  Kb (C7H5O2) = 1.5x10–10
 A) 5.91 B) 8.09 C) 0.38 D) 13.62

3.

When a weak acid is titrated with a strong base, the pH at the equivalence point is
 A) greater than 7.0 B) equal to 7.0 C) less than 7.0 D) equal to the pKa of the acid

4.

Which of the following will form a buffer when dissolved in water to make 1 L of solution?
 A) 0.2 mol of NaCl and 0.2 mol HNO3 B) 0.2 mol NaOH and 0.2 mol HCl C) 0.4 mol HC2H3O2 and 0.4 mol NaOH D) 0.4 mol NH3 and 0.2 mol HCl

5.

A 20.0-mL sample of 0.25M HCl is titrated with 0.15M NaOH.  What is the pH of the solution after 30.0 mL of the base have been added?
 A) 1.6 B) 2 C) 1 D) 1.2

6.

The solubility of Cu(IO3)2 in water is 3.27x10–3 M.  What is the Ksp?
 A) 3.50x10–8 B) 2.14x10–5 C) 1.40x10–7 D) 4.28x10–5

7.

What is the [H3O+] in a solution that consists of 1.5 M NH3 and 2.5 M NH4Cl? (Kb = 1.8 x10–5)
 A) 9.3 x10–10 M B) 1.1 x10–5 M C) 3.3 x10–10 M D) 3.0 x10–5 M

8.

Which of the following has the highest buffer capacity?
 A) 0.10 M H2PO4– / 0.50 M HPO42– B) 0.50 M H2PO4– / 0.10 M HPO42– C) 0.10 M H2PO4– / 0.10 M HPO42– D) 0.50 M H2PO4– / 0.50 M HPO42–

9.

What is the pKa for the acid HA if a solution of 0.65M HA and 0.85M NaA has a pH of 4.75?
 A) 5.02 B) 4.63 C) 4.87 D) 4.48

10.

Which of the following mixtures would be a buffer system?
 A) CH3COOH , NaH2PO4 B) HSO4– , HSO3– C) H2CO3 , HCO3– D) H2PO4– , HCO3–

11.

What will be the effect of adding 0.5 mL of 0.1 M HCl to 100 mL of a phosphate buffer in which [H2PO4] = [HPO42–] = 0.35 M?
 A) The pH will increase significantly B) The pH will decrease significantly C) The pH will increase slightly D) The pH will decrease slightly

12.

Which of the following statements is true for the titration of a weak acid with a strong base?
 A) At the equivalence point, the [H+] equals the ionization constant of the acid B) The pH is 7 at the equivalence point C) The graph of pH versus the volume of base added rises gradually at first and then much more rapidly D) The graph of pH versus the volume of base added shows no sharp rise