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1 . A sample of weak acid was titrated against NaOH, and it required 14.53 mL to

ID: 967741 • Letter: 1

Question

1. A sample of weak acid was titrated against NaOH, and it required 14.53 mL to be fully neutralized. Calculate the volume of NaOH required to reach 60% neutralization.

This question seems really simple, so thats why I'm asking just to be sure I did mine right. My answer came to 8.72 mL NaOH.

2. Another aliquot of the same weak acid solution was combined with 9.15 mL of NaOH, and the pH was determined to be 3.57.

a. Calculate the percentage of acid that was neutralized.

b. Calculate the percentage of acid that was neutralized.

c. Calculate the pKa of the weak acid.

Pre-lab questions, so I need work shown so i can see how you derived with the answer. Thanks!

Explanation / Answer

1) For full neutralisation, 14.53 ml of NaOH is required

Thus, for 60% neutralisation, volume of NaOH required = 0.6*14.53 = 8.718 ml

2) % age neutralisation = (9.15/14.53)*100 = 62.973 %

[H+] = 10-pH = 2.692*10-4 M

***** Provide the initial concentration of the weak acid to find the pKa value.