The 1/2 equivalent point in a titration curve

In summary, the 1/2 equivalent point in a titration curve refers to the stage where half of the analyte has been neutralized by the titrant. At this point, the concentration of the weak acid equals the concentration of its conjugate base, resulting in a pH equal to the pKa of the acid. This point is significant for determining the buffering capacity and the optimal pH range for a reaction, as it indicates the maximum effectiveness of the buffer system.
  • #1
Saba
10
2
TL;DR Summary
It is pretty challenging for me to understand how the 1/2 equivalent point in a titration curve (when either acid or base is weak) the pH = pKa.
I researched about the formula that is used to get this, but I couldn't quite understand that.
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  • #2
What are expected concentrations of the remaining, non-neutralized titrated acid and its conjugate base at half point?

What is ratio of these concentrations equal to?

What is log of that?
 
  • #3
From the equation above (the Henderson-Hasselbach equation if I remember correctly), the half equivalent point is when the concentrations of the acid and its conjugate base are equal. Any number divided by itself is 1 (one). The log of 1 is 0 (zero), so therefore pH = pKa
 

FAQ: The 1/2 equivalent point in a titration curve

What is the 1/2 equivalent point in a titration curve?

The 1/2 equivalent point in a titration curve is the point at which half of the analyte has been neutralized by the titrant. This occurs when the moles of titrant added is equal to half of the moles of analyte present in the solution.

How is the 1/2 equivalent point determined in a titration curve?

The 1/2 equivalent point in a titration curve can be determined by finding the volume of titrant added at the point where the pH is equal to the pKa of the weak acid or base being titrated. This indicates that half of the analyte has been neutralized.

Why is the 1/2 equivalent point important in a titration curve?

The 1/2 equivalent point is important because it can be used to determine the pKa of the weak acid or base being titrated. It also helps in calculating the concentration of the analyte in the solution.

What does the shape of the titration curve look like at the 1/2 equivalent point?

At the 1/2 equivalent point, the titration curve will have a steep slope, indicating a rapid change in pH as more titrant is added. This is because the solution is at its buffering capacity at this point.

How does the 1/2 equivalent point differ from the equivalence point in a titration curve?

The 1/2 equivalent point is the point at which half of the analyte has been neutralized, while the equivalence point is the point at which all of the analyte has been neutralized by the titrant. The equivalence point is determined by a sharp change in pH, while the 1/2 equivalent point is determined by the pKa of the weak acid or base being titrated.

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