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Buffer

#### Q. Which of the following solutions would be the best choice for preparing a buffer with a pH=8.0? A.boric acid (Ka= 5.8 × 10−10) and sodium borate. B.hypochlorous acid (Ka= 3.5 × 10−8) and sodium hypochlorite. C.acetic acid (Ka= 1.8 × 10−5) and sodium acetate. D.formic acid (Ka= 1.8 × 10−4) and sodium formate. E.All of these solutions would be equally good choices for making this buffer.

Solved • Apr 12, 2020

Buffer

#### Q. What is the pH of a buffer solution in which [A–]= 2[HA] and the pKa of HA is 4.5? A.2.5. D.4.8. B.4.2. E.6.5. C.4.5

Solved • Apr 12, 2020

Buffer

#### Q. What is the pH of a buffer solution in which [HA] = [A−]? A.pH =1. D.pH =pOH. B.pH =Ka. E.pH =7.0. C.pH =pKa

Solved • Apr 12, 2020

Buffer

#### Q. 7.50 mL of a 0.150 M solution of NaOH was added to 20.00 mL of a weak acid, HA. The pH of the resulting solution was 3.50. KA of the acid is 2.82 x 10^-4 . Calculate the concentration of the acid used to prepare the solution. Use the simultaneous equation method for the calculation. Note any simplifying assumptions made in the derivation.

Solved • Apr 10, 2020

Buffer

#### Q. a) 20.0 mL 0.1 M acetic acid + 20 mL 0.1 M HCl + 20 mL 0.1 M NaOH b) 40 mL 0.1 M HCl + 20 mL 0.1 M NaOH + 60 mL 0.1 M sodium acetate c) 60 mL 0.1 M sodium acetate + 20 mL HCl + 20 mL 0.1 M acetic acid d) 40 mL 0.1 M NaOH + 20 mL sodium acetic acid + 40 mL 0.1 M sodium acetate You are given 0.1 M solutions of HCl, NaOH, acetic acid, sodium acetate Indicate if any of the solutions a-d given above is a buffer solutions, if not, how would you convert it into a buffer solution. You can add requisite amount of any one of the 0.1 M solutions of HCl, NaOH, acetic acid or sodium acetate

Solved • Apr 9, 2020

Buffer

#### Q. For 520.0 mL of a buffer solution that is 0.155 M in HC2H3O2 and 0.140 M in NaC2H3O2, calculate the initial pH and the final pH after adding 0.020 mol of HCl.

Solved • Apr 8, 2020

Buffer

#### Q. Which combination of the following components would make a good buffer solution? a.significant amounts of both a strong acid and a strong base. b.significant amounts of both a weak acid and a strong acid. c.significant amounts of both a weak acid and its conjugate base. d.small amounts of both a weak acid and its conjugate base. e.small amounts of both a strong acid and a strong base

Solved • Apr 7, 2020