AP Acids and Bases 2

Question 1

A buffer solution is prepared by mixing 0.300 mol of acetic acid (Ka = 1.8 × 10⁻⁵) and 0.200 mol of sodium acetate in 1.00 L of solution. What is the pH of this buffer?

Accepted Answer

4.57

Answer

4.87

Answer

4.44

Answer

5.05

Question 2

Which of the following best explains why HCl is a strong acid while HF is a weak acid, given that fluorine is more electronegative than chlorine?

Accepted Answer

The H–F bond is stronger than the H–Cl bond, making it harder to donate the proton

Answer

Fluorine is too small to stabilize the negative charge after bond breaking

Answer

HCl dissociates via a heterolytic mechanism while HF dissociates homolytically

Answer

HF forms fewer hydrogen bonds in solution than HCl

Question 3

A student titrates 25.00 mL of 0.100 M NH₃ (Kb = 1.8 × 10⁻⁵) with 0.100 M HCl. What is the pH at the equivalence point?

Accepted Answer

5.13

Answer

8.87

Answer

7.00

Answer

4.74

Question 4

According to Lewis acid-base theory, which species acts as the Lewis acid in the reaction: BF₃ + NH₃ → F₃B–NH₃?

Accepted Answer

BF₃, because it accepts an electron pair from NH₃

Answer

NH₃, because it donates an electron pair to BF₃

Answer

BF₃, because it donates a proton to NH₃

Answer

F⁻, because it is released during the reaction

Question 5

A 0.050 M solution of a monoprotic weak acid has a pH of 3.40. What is the percent dissociation of this acid?

Accepted Answer

8.0%

Answer

0.80%

Answer

0.40%

Answer

4.0%

Question 6

Which of the following aqueous solutions has the highest pH?

Accepted Answer

0.10 M NaC₂H₃O₂ (sodium acetate)

Answer

0.10 M NaCl

Answer

0.10 M NH₄Cl

Answer

0.10 M HCl

A buffer solution is prepared by mixing 0.300 mol of acetic acid (Ka = 1.8 × 10⁻⁵) and 0.200 mol of sodium acetate in 1.00 L of solution.What is the pH of this buffer?

A buffer solution is prepared by mixing 0.300 mol of acetic acid (Ka = 1.8 × 10⁻⁵) and 0.200 mol of sodium acetate in 1.00 L of solution.
What is the pH of this buffer?