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Lab 6B – Find the Ka Using a Titration Curve
1) As base is added to the buffer region of the acid titration curve, what is the conjugate-acid being converted too? (1 pt)
2) As base is added to the buffer region of the acid titration curve, why doesn’t the pH change very much? (1 pt)
3) What does the middle of the buffer region (usually the point at which the curve is flattest) indicate, meaning, what is happening at that point? (1 pt)
4) True or False? Is the middle of the buffer region called the half-equivalence point? (1 pt)
5) What does the half-equivalence point equal? (1 pt)
6) If the pH at the equivalence point equals 8.72, and the pH at the half-equivalence point equals 4.61, what is the pKa of the acid? (1 pt)
7) If the pH at the half-equivalence point equals 4.61, what is the value of the Ka of the acid? (1 pt)
Lab 6B – Find the Ka Using a Titration Curve Answer
- Conjugate base
- Because the added base is consumed by the weak acid, forming conjugate base of the acid. The amount of the weak acid decreases while the amount of the conjugate base increases. The amount of H+ ions does not change very much. This what makes the pH of the solution from changing dramatically.