Question

1. A solution has [HC7H5O2] = 0.100 M and [Ca(C7H5O2)2] = 0.200 M. Ka = 6.3 × 10-5 for HC7H5O2. The solution volume is 5.00 L. What is the pH of this solution after 5.00 mL 10.0 M HCl is added?

2. Which of the following solution(s) is a buffer?

		100 mL of 0.1 M acetic acid mixed with 25 mL of 0.5 M NaOH
		50 mL of 0.1 M acetic acid mixed with 25 mL of 0.05 M sodium acetate
		50 mL of 0.1 M acetic acid mixed with 25 mL of 0.05 M NaOH
		50 mL of 0.1 M acetic acid mixed with 25 mL of 0.2 M HCl
		50 mL of 0.1 M sodium acetate mixed with 25 mL of 0.05 M NaOH

3. Two buffer solutions of the same pH are prepared. After adding 15 mmol of acid to 250 mL of one solution, the pH changes by 0.02 pH units. Adding 15 mmol of acid to 250 mL of the second solution results in a 0.05 pH unit change. Which statement most accurately describes the difference between the two buffer solutions?

		The second solution has a lower concentration of conjugate base than the first solution.
		The first solution has a lower buffer capacity than the second solution.
		The second solution has a higher acid to conjugate base ratio than the first solution.
		The first solution has a higher concentration of conjugate acid than conjugate base.
		The first solution has a higher capacity than the second solution.