how to find ka from titration curve This is a topic that many people are looking for. cfiva.org is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, cfiva.org would like to introduce to you Find the Ka Using a Titration Curve. Following along are instructions in the video below:
Halloween guys trick or treat oh you want to treat well here let me show show you how to find the ka of an acid from a titration curve. When start with acid. And you add base to the equivalence point.
Now the first thing is if youre trying to find the ka with a titration you dont need to go any farther than the equivalence point. But maybe you did i dont care so here we go at the equivalence point. We have added just as much base as we have acid thats the definition for equivalence point.
What youll notice about the titration curve is that there is a buffer region. Here. The buffer region is the region.
Where youve added just enough base that you have some conjugate base in solution. But you also have some acid in solution. So as you keep adding base rather than creating more ohs or consuming.
More h. Pluses. Youre actually just converting conjugate acid into conjugate base.
So the ph doesnt change very much because the h concentration isnt being affected by you adding base heres the point. Though the best place for the buffer reagent or where the buffer is flattest or the middle of the buffer region is the point at which youve added half as much base as you have half as much base as you started with of acid. Which means that in your solution your concentration of base is equal to the concentration of your acid.
You started with a full amount of acid and youve titrated half of it away. So lets say the start at 20. You started at 20 half of thats gone and you had added.
Ten of these see how halfway gets you so the base equals. The acid especially since you serve as the euro base anyways. Tell goats now the greatest part about the buffer region is we have a special equation called the henderson hasselbalch equation or henderson hasselbach.
I dont know ph equals pka plus log concentration of base acid and the greatest part about this point in the buffer region. Exactly halfway to equivalence point in this case half of eight sixteen point eight two is eight point three one milliliters. The ph at that point has the concentration of base and concentration of acid equal.
Which means base divided by acid is one and the log of 1 is 0. So at this point exactly halfway to equivalence whatever your ph was there i dont know three point six two that is the pka for the acid that youre using and lucky for you theres a nice easy way to figure. It the ka from the pka.
If the pk. A is three point six to the ka is ten to the negative three point six two on your calculator. I type three point six two negative and then i use the ten to the power of button.
And i get two point four times ten to the minus four and thats how you find the ka of an acid from the titration curve. The pka of the acid is the same as the ph halfway to equivalence happy halloween best of luck. .
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