Buffer Solution

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JChen_2I
Posts: 107
Joined: Fri Aug 09, 2019 12:17 am

Buffer Solution

Postby JChen_2I » Wed Feb 12, 2020 11:46 am

This is a problem from Hannah's acid and base review session:
What is the initial pH of a buffer solution consisting of .400M acetic acid (CH3COOH) and .250M KCH3CO2? The Ka for acetic acid is 1.78 x 10^-5
The answer I got was a pH of 4.545 and I was wondering if someone could confirm that this is correct?
Thanks!

Robert Tran 1B
Posts: 118
Joined: Thu Jul 11, 2019 12:15 am

Re: Buffer Solution

Postby Robert Tran 1B » Wed Feb 12, 2020 1:35 pm

I also got pH = 4.545!

Natalie Benitez 1E
Posts: 100
Joined: Fri Aug 02, 2019 12:15 am

Re: Buffer Solution

Postby Natalie Benitez 1E » Mon Feb 17, 2020 1:57 pm

What exactly does a bufffer solution do and how do they relate to strong or weak acid and bases.

Deepika Reddy 1A
Posts: 125
Joined: Thu Jul 11, 2019 12:15 am

Re: Buffer Solution

Postby Deepika Reddy 1A » Mon Feb 17, 2020 2:03 pm

Buffer solutions can only be made with a weak acid and its conjugate base or a weak base and its conjugate acid. This is because a strong acid or strong base completely dissociate in a solution so that at the end, none of the substance is present in the solution at the end of the reaction. For weak acids and weak bases, they only partially dissociate so both species, the weak acid or base, and their conjugate is present in solution. Therefore, they can act as buffers and work to keep the pH of a solution stable.

Mitchell Koss 4G
Posts: 128
Joined: Sat Jul 20, 2019 12:17 am

Re: Buffer Solution

Postby Mitchell Koss 4G » Mon Feb 17, 2020 2:18 pm

Buffers allow for small changes. If only strong acids or bases were used, then small changes wouldn't really be possible.


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