PH after titration of Weak Acid with a Strong Base

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SUMMARY

The discussion centers on calculating the pH at the equivalence point of titrating 0.1006M acetic acid (CH3COOH) with 0.2012M sodium hydroxide (NaOH). The correct approach involves recognizing that at the equivalence point, the solution contains the sodium salt of the weak acid, which affects the pH. The pH should be above 7, as the resulting solution is basic due to the presence of the acetate ion (A-). The confusion arose from miscalculating pH using the dissociation constant (Ka) instead of considering the properties of the sodium salt in water.

PREREQUISITES
  • Understanding of weak acid and strong base titration principles
  • Knowledge of pKa and Ka calculations
  • Familiarity with ICE tables for equilibrium calculations
  • Basic concepts of pH and pOH relationships
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  • Study the properties of conjugate bases in weak acid-strong base titrations
  • Learn how to calculate pH at the equivalence point for various acid-base titrations
  • Explore the concept of buffer solutions and their pH stability
  • Investigate the role of ionic strength in titration curves
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Chemistry students, educators, and laboratory technicians involved in acid-base titration experiments and pH calculations.

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Homework Statement


Titrating .1006M CH3COOH with .2012M NaOH. pKa=4.74, Ka=1.8*10^-5
What is the pH at the equivalence point of the titration?


Homework Equations


pKa = -log(Ka) pH = -log[H+]


The Attempt at a Solution



Alright, after setting up an ICE table (in order to find [H+] at the equivalence point) I realized that when you work it out Ka = [H+], however when I plugged that in I got a pH in th 4-5 range when it should be above 7.
Here is my Ka reasoning
Ka = [A-][H+]/[HA]
Ka = [Co+x][x]/[Co-x] Co = Initial Concentration
x is very small (Weak acid, no/little disassociation)
Ka = x
Ka = [H+]


Am I missing something or is my logic just wrong? Anything that could point me in the correct direction would be greatly appreciated.
 
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The pH at equivalence is the same as if you dissolved the sodium salt in water, without any acid or base. Now, you calculation should be based on just the effect of the sodium salt alone in the water.
 
Late answer but i came across this question when i was looking for the same answer.

Don't forget the answer your getting is pOH!
Therefore pH = 14 - pOH (where your pOH will be between 5-6 for this type of question)
pH = > 7
 

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