[smellatron]

I have a test tomorrow and this is from the exam last semester and it has me baffled.

A 0.150 M solution of HA is titrated with 10 mL of a 0.150 M NaOH solution. Based on the table above, the best indicator for this reaction is __________. The Kb of A- is 1.47 × 10-11.

The answer is thymol blue that has a pH range of 8.0-9.6. I am utterly confused on how to find the pH. To me it would seem I need the volume of the HA?? I want the indicator to go over the 1/2 equivalence point or the equivalence point (Pretty sure the equivalence point)?? Just a pointer in the right direction would be great.

Thank you for your time.

[Borek]

Voulme of HA will be given by the reaction stoichiometry.

http://www.titrations.info/acid-base-titration-end-point-detection

http://www.titrations.info/acid-base-titration-equivalence-point-calculation