1. Tahani Alshehri Tmalshehri@ksu.edu.sa 2009
Preparation of the buffer solutions, titration of amino acid and there buffering capacity
Tahani Alshehri
2009

2. Objective
To Study the nature of the buffers

3. Introduction & principle
Buffer solution
a solution which resist the changes in pH upon addition of small amounts of acid or base, or upon dilution
Is a the weak acid and its salt in strong base in a buffer a solution .

4. Acidic buffer solutions
An acidic buffer solution is simply one which has a pH less than 7.
Acidic buffer solutions are commonly made from a weak acid and one of its salts - often a sodium salt.

5. Alkaline buffer solutions
An alkaline buffer solution has a pH greater than 7.
Alkaline buffer solutions are commonly made from a weak base and one of its salts.

6. ? ethanoic acid and sodium ethanoate
ammonia solution and ammonium chloride solution

7. Acidic buffer solutions
We'll take a mixture of acetic acid and sodium acetate as typical.
acetic acid is a weak acid

8. Buffers are main important in regulating the pH of the body fluids and tissues within limits consistants with life and normal function
Many body chemical reaction including those catalyzed by enzyme require pH control which is provided by buffers
Mammalian tissue in the resting state have a pH of about 7.4

9. Henderson–Hasselbalch equation
The pH of the buffer is given by Henderson–Hasselbalch equation
Which for practical purposes , becomes
Here, pKa is − log(Ka) where Ka is the acid dissociation constantof the acid

10. How do buffer solutions work?
A buffer solution has to contain compounds which will remove any hydrogen ions or hydroxide ions that you might add to it - otherwise the pH will change.
Acidic and alkaline buffer solutions achieve this in different ways.