Carbonate/bicarbonate buffering of ph

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In summary, buffers are substances that can increase or decrease the pH of a solution depending on its initial value. For example, sodium bicarbonate can increase the pH of water until it reaches 8.4, at which point it stops the process. However, if the initial pH is above 8.4, bicarbonate will release H+ ions and lower the pH. This process continues until the pH reaches 8.4. The article also warns against relying on unreliable sources for information, recommending a more accurate link for reference.
  • #1
caliban07
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I recently read an article that a buffer that increases alkalinity to achieve a desired ph has it's in preferred ph value.

For example, sodium bicarbonate holds water at a ph of 8.4.

The article also went on to state that buffers don't always raise ph they can lower it too.

The article states:

"Below 8.4, Bicarbonate absorbs H+ ions and the equation moves to the left, making the water more alkaline. This continues until the pH reaches 8.4 when the process stops.

Above 8.4, Bicarbonate releases H+ ions and the equation moves to the right, making the water more acidic. This continues until the pH is 8.4 when the process stops"

The second paragraph doesn't make sense. How can bicarbonate release H+ ions and move ph down if we are adding a base?

Here is the full article it's only a page long.

(link removed by Borek)
 
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  • #2
My advice: don't bother, this article is full of nonsense.

Actually it is so bad I am deleting the link from your post.
 
  • #3
Borek said:
My advice: don't bother, this article is full of nonsense.

Actually it is so bad I am deleting the link from your post.
Ok perhaps you could provide me with a more accurate link?
 
  • #5


Thank you for sharing this article on carbonate/bicarbonate buffering of pH. I would like to provide some additional information and clarification on this topic.

First, it is important to understand that buffers are substances that resist changes in pH when an acid or base is added. They do this by absorbing or releasing H+ ions to maintain a relatively constant pH. In the case of carbonate/bicarbonate buffering, the bicarbonate ion (HCO3-) acts as a weak base and can absorb excess H+ ions to prevent a decrease in pH.

In the article, it is correct that sodium bicarbonate (NaHCO3) can hold water at a pH of 8.4 by absorbing H+ ions. However, it is important to note that this is the maximum pH at which the buffer can function. If the pH of the water is already above 8.4, the bicarbonate ion will actually release H+ ions to lower the pH. This is because the equilibrium equation for bicarbonate (HCO3- + H+ ⇌ H2CO3) shifts to the right at higher pH levels, resulting in the release of H+ ions.

As the article mentions, the process of buffering can continue until the pH reaches 8.4, at which point the equilibrium is balanced and the buffer can no longer absorb or release H+ ions. This is why the buffer is considered to have a preferred pH value of 8.4.

I agree with your confusion about the second paragraph of the article. It is important to note that buffers can only release H+ ions if there is already an excess of H+ ions present. In the case of carbonate/bicarbonate buffering, this would only occur if the pH is above 8.4. And even then, the release of H+ ions would not be enough to significantly decrease the pH.

In summary, carbonate/bicarbonate buffering is a complex process that involves the equilibrium between bicarbonate and carbonic acid (H2CO3). The buffer can absorb or release H+ ions to maintain a pH of 8.4, but it cannot lower the pH below this point. I hope this helps to clarify any confusion and further your understanding of this important buffering system.
 

1. What is the purpose of carbonate/bicarbonate buffering in pH regulation?

Carbonate/bicarbonate buffering is an important mechanism in maintaining a stable pH in many biological systems. It helps to resist changes in pH by absorbing excess hydrogen ions (H+) or hydroxide ions (OH-) that may be added to the system, thus preventing drastic changes in pH levels.

2. How does carbonate/bicarbonate buffering work?

Carbonate/bicarbonate buffering involves the reversible reactions between carbon dioxide (CO2), water (H2O), carbonic acid (H2CO3), bicarbonate ions (HCO3-), and hydrogen ions (H+). When the pH of a system decreases, carbonic acid dissociates into bicarbonate ions and hydrogen ions, thus preventing a drastic decrease in pH. Likewise, when the pH of a system increases, bicarbonate ions can combine with hydrogen ions to form carbonic acid, preventing a drastic increase in pH.

3. What is the role of carbonic anhydrase in carbonate/bicarbonate buffering?

Carbonic anhydrase is an enzyme that catalyzes the conversion of carbon dioxide and water into carbonic acid. It plays a crucial role in the carbonic acid-bicarbonate buffering system by facilitating the rapid conversion of carbon dioxide to maintain equilibrium between carbonic acid and bicarbonate ions.

4. How does temperature affect carbonate/bicarbonate buffering?

Temperature can affect carbonate/bicarbonate buffering by influencing the rate of reactions involved in this mechanism. Higher temperatures can increase the rate of carbonic acid dissociation, leading to a decrease in pH. Conversely, lower temperatures can slow down the rate of reaction, resulting in a more stable pH.

5. What are some factors that can disrupt carbonate/bicarbonate buffering?

Carbonate/bicarbonate buffering can be disrupted by various factors, such as changes in temperature, changes in carbon dioxide levels, and the presence of other compounds that can react with carbonic acid or bicarbonate ions. Additionally, disturbances in the equilibrium between carbonic acid and bicarbonate ions can also disrupt the buffering system and cause changes in pH levels.

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