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Topic: definitions of buffer solution  (Read 377 times)

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Offline Win,odd Dhamnekar

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definitions of buffer solution
« on: April 28, 2021, 05:36:15 AM »
Are the following two definitions of buffer solution same, correct, valid  and equal in meaning.
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Offline Babcock_Hall

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Re: definitions of buffer solution
« Reply #1 on: April 28, 2021, 09:03:05 AM »
What are your thoughts?

Offline Win,odd Dhamnekar

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Re: definitions of buffer solution
« Reply #2 on: April 28, 2021, 09:21:15 AM »
 In my opinion, both definitions of buffer solution are same, correct, valid and equal in meaning.
Any science consists of the following process.
 1) See 2) Hear 3) Smell if needed 4) Taste if needed
5) Think 6) Understand 7) Inference 8) take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

Offline Babcock_Hall

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Re: definitions of buffer solution
« Reply #3 on: April 28, 2021, 10:01:00 AM »
I don't see anything the matter with either definition.

Offline Meter

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Re: definitions of buffer solution
« Reply #4 on: April 28, 2021, 11:28:30 AM »
Why not let the definition be "a system in solution that resists change to pH" and allow for different mechanisms?

Offline Win,odd Dhamnekar

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Re: definitions of buffer solution
« Reply #5 on: April 28, 2021, 12:05:47 PM »
 Both of these definitions of buffer solution are given by the authors of chemistry textbook.

In the first definition, Authors says " You can treat buffer solutions quantitatively if you use the appropriate Ka or Kb and recognize the role of common ion".

What does it mean? What message authors want to give to the readers? Would anyone elaborate on this topic?
Any science consists of the following process.
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5) Think 6) Understand 7) Inference 8) take decision [Believe or disbelieve, useful or useless, healthy or unhealthy, cause or effect, favorable or unfavorable, practical or theoretical, practically possible or practically impossible, true or false or  any other required criteria]

Offline Meter

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Re: definitions of buffer solution
« Reply #6 on: April 28, 2021, 02:15:25 PM »
Both of these definitions of buffer solution are given by the authors of chemistry textbook.

In the first definition, Authors says " You can treat buffer solutions quantitatively if you use the appropriate Ka or Kb and recognize the role of common ion".

What does it mean? What message authors want to give to the readers? Would anyone elaborate on this topic?
He is probably referring to the Henderson-Hasselbalch equation which is pH = pKa + log([A-]/[HA]).

Another version exists where you use pKb instead, and as you know, pKa and pKb depend on Ka and Kb. You also derive the HH equation from Ka or Kb.

If it's not that, I don't know what he's talking about.

As for the common ion effect, recall that the concentration ratio uses equilibrium concentrations. When calculating such concentrations (like with ICE tables), one must take into account the common ion effect.

Offline Babcock_Hall

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Re: definitions of buffer solution
« Reply #7 on: April 28, 2021, 03:33:09 PM »
Using the H-H equation allows one to estimate how much base must be added to a weak acid, in order to prepare a buffer, among other things.  If I had written the passage, I might have mentioned that ionic strength affects the practical pKa values.

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