CHEMICAL BUFFERS – APPLICATIONS
PART A:
Go to http://www.bbc.co.uk/dna/h2g2/A8819652 and read ‘Regulation of Blood pH’.
1. What is the ideal pH of your blood?
7.2-7.6
2. How does the human body deal with changes in pH?
Buffers, the lungs, and the kidneys are three interconnected objects that are necessary for this.
For keeping the H+ ion concentration at a specific level, buffers are molecules that either take in
or release ions. Blood buffers, which include hemoglobin (Hb), certain proteins (Prot), and
phosphates, serve as the first line of defense in the event of abrupt pH fluctuations. Too many H+
ions are present in the blood when the pH is too low, and the blood becomes overly acidic. The
buffers will try to remove the extra. In contrast, a deficiency in H+ ions cause the blood to become
too basic, which causes the buffers to release H+ ions.
The body's pH balance is critically regulated by the lungs. Via buffer reactions, the pH can be
quickly corrected, but this is not a permanent fix. The hydrogen carbonate ion is a significant buffer
in this (HCO3-). Although the HCO3- buffer processes can be reversed, they are prevented from
doing so if carbon dioxide (CO2) is eliminated through breathing. The pH of the blood is raised
because of the removal of extra H+ ions. You can alter the blood pH by changing the rate of
breathing, which will change how much CO2 is released. Respiratory alkalosis is caused by
hyperventilating, while hyperventilating causes blood pH to drop (respiratory acidosis).
By removing extra acids or bases from the blood, the kidneys are essential for maintaining blood
pH balance. If metabolism is not controlled, it creates more acids than bases, which can result in
metabolic acidosis. Nephrons in the kidneys filter blood to create a filtrate. Ions like HCO3- and H+
are selectively reabsorb able or secreted by certain parts of the nephron. Depending on the blood
pH, about 85% of HCO3- is reabsorbed, and the remaining HCO3- undergoes a reaction with
released H+ and is expelled. The removal of H+ ions from the blood is also aided by HPO42-. An
amino acid called glutamine can be broken down into NH4+ and HCO3-. While HCO3- is returned
to the bloodstream and the body excretes NH4+ in urine, the blood pH is raised. By checking the
amounts of NH4+ in the urine, urologists can identify respiratory acidosis.
PART B:
Go to http://www.chemistry.wustl.edu/~edudev/LabTutorials/Buffer/Buffer.html and read ‘How
Buffers Work: A Quantitative View’.
1. How do buffers work? LINK NOT WORKING
2. What is the carbonic-acid-bicarbonate buffer? Use equations to explain. LINK NOT WORKING
3. What ion is added to the blood during physical exercise? LINK NOT WORKING
4. What other organs are involved in monitoring blood pH and how? LINK NOT WORKING
5. What is the phosphate buffer and how is it involved in buffering blood pH? LINK NOT WORKING
PART C:
Using reputable sources on the internet, provide some information about another application of buffers
in the real world. Be sure to include information about specific buffer systems that are used and why.
In water treatment, one specific buffer system commonly used to control and stabilize pH is the
carbonate buffer system. The carbonate buffer system consists of a mixture of carbonic acid (H2CO3),
bicarbonate ions (HCO3-), and carbonate ions (CO32-).
When carbon dioxide (CO2) dissolves in water, it reacts with water to form carbonic acid:
CO2 + H2O ↔ H2CO3
Carbonic acid then dissociates into bicarbonate ions and hydrogen ions:
H2CO3 ↔ HCO3- + H+
The bicarbonate ions can further react with water to form carbonate ions and additional hydrogen ions:
HCO3- ↔ CO32- + H+
This equilibrium among carbon dioxide, carbonic acid, bicarbonate ions, and carbonate ions helps
to maintain the pH of water within a specific range. If the pH starts to increase (becoming more alkaline),
carbon dioxide will dissolve in water to form carbonic acid, which will then donate hydrogen ions to lower
the pH. Conversely, if the pH starts to decrease (becoming more acidic), the equilibrium shifts to favor the
formation of bicarbonate ions and carbonate ions, which can accept hydrogen ions and help raise the pH.
By adjusting the concentrations of carbon dioxide, bicarbonate ions, and carbonate ions, water
treatment facilities can effectively control and stabilize the pH of water supplies for different purposes,
ensuring it meets the desired standards and remains suitable for various applications.