Henderson-Hasselbalch equation

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Hamilton Oh Dis 3L
Posts: 30
Joined: Fri Sep 25, 2015 3:00 am

Henderson-Hasselbalch equation

Postby Hamilton Oh Dis 3L » Fri Dec 04, 2015 8:16 pm

Am I correct in saying that the Henderson-Hasselbalch equation only works for weak acids and bases that have very small K values (x<10^-4)?

Austin Qiu 1A
Posts: 21
Joined: Fri Sep 25, 2015 3:00 am

Re: Henderson-Hasselbalch equation

Postby Austin Qiu 1A » Fri Dec 04, 2015 8:28 pm

I thought so too, but I read on chemwiki that the best range to get accurate approximations is when the pKa=5-9 (so when Ka=1e-5). Now I'm not so sure either...

Vanessa A 3F
Posts: 29
Joined: Fri Sep 25, 2015 3:00 am

Re: Henderson-Hasselbalch equation

Postby Vanessa A 3F » Sat Dec 05, 2015 5:36 pm

In this class we will mostly get questions where we can't use the HH equation. Unless the question has the word "buffer" in it, then you can go ahead and use it. Otherwise it's hard to tell

Molly Maloney 1B
Posts: 6
Joined: Fri Sep 25, 2015 3:00 am

Re: Henderson-Hasselbalch equation

Postby Molly Maloney 1B » Wed Jul 27, 2016 12:17 pm

Can the Henderson-Hasselbalch equation be used to find P[OH]?

Edgar Khachatryan 3G
Posts: 20
Joined: Fri Jul 15, 2016 3:00 am

Re: Henderson-Hasselbalch equation

Postby Edgar Khachatryan 3G » Mon Nov 28, 2016 8:09 pm

The Henderson-Hasselbalch equation is used to calculate the pH of solution containing an acid and its conjugate base as a salt OR to calculate the pOH of a base and its conjugate acid as a salt.

pH= pKa + log(A-/HA)

pOH= pKb + log(BH+/BH)


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