× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
Home Q & A Board Science-Related Homework Help Chemistry (Moderator: Laser_3)
New Topic  
Fightboy Fightboy
wrote...
Posts: 29
Rep: 2 0
9 years ago
Trifluoroacetic acid has a pka of 0.23. If this compound is a solution with a pH of 4.23, what is the ratio of trifluoroacetic acid to trifluoroacetate?
Would the answer be 1:10,000?? That's the answer i got but the answer key said 1:1,000
Read 357 times
1 Reply

Related Topics

Replies
rsb
wrote...
#1
9 years ago
Found this online:

Quote
use the henderson-hasslebach equation
pH = pKa + log ( [A-]/[HA] )
4.23 = 0.23 + log (A-/HA)
4.00 = log [A-/HA]
10^4.00 = log A-/HA]
You will have 10000 times more conjugate base than acid, or 0.0001 acid to each conjugate base.

This is a horrible buffer, (as you can see).
For a good buffer we want the pKa to be as close to the pH as possible, that way we can have equal parts weak acid and conjugate base
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  1237 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Related Images
  
 132
  
 414
  
 306
Your Opinion
What's your favorite funny biology word?
Votes: 328
Previous poll results: Which country would you like to visit for its food?