Solving Henderson-Hasselbalch Equation: Buffer Question

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SUMMARY

The discussion focuses on solving the Henderson-Hasselbalch equation to determine the amount of 2 M KOH required to adjust the pH of a 50 mL solution of 0.2 M formic acid (pKa 3.75) to 3.75. The correct calculation reveals that 2.5 mL of KOH must be added. Participants express confusion about the steps involved in using the Henderson-Hasselbalch equation and the chemical interactions occurring when KOH is introduced to the formic acid solution.

PREREQUISITES
  • Understanding of the Henderson-Hasselbalch equation
  • Knowledge of acid-base chemistry, specifically regarding weak acids and their conjugate bases
  • Familiarity with pKa and Ka values
  • Basic skills in stoichiometry for calculating molarity and volume
NEXT STEPS
  • Study the Henderson-Hasselbalch equation in detail
  • Learn about the dissociation of weak acids and their behavior in buffer solutions
  • Explore stoichiometric calculations involving titration of weak acids with strong bases
  • Review examples of buffer systems and their pH adjustments
USEFUL FOR

This discussion is beneficial for chemistry students, educators, and laboratory technicians who are working with buffer solutions and need to understand the application of the Henderson-Hasselbalch equation in practical scenarios.

tmumby
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BIOCHEM: buffer question!

You have a sample of 50 mL of 0.2 M formic acid, which has a pKa of 3.75 (Ka = 1.78x10-4). How much 2 M KOH must be added to adjust the pH of the sample to 3.75?

The correct answer is 2.5mL

I tried using the henderson hasslebach equation and I just cannot wrap my head around how to go about solving it. It should be simple but i get into way to many steps and still come out with the wrong answer HELPPP
 
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What happens in the solution of the formic acid when you add KOH?
 

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