How Do Buffers React to Strong Acids and Bases?

In summary, the conversation discusses the concept of buffers in chemistry and their role in maintaining pH levels. The speaker asks for help in understanding the effects of adding a strong base or acid to a buffer system, and how it affects the concentration of H+ ions. They also inquire about the discrepancies between experimental and theoretical values for the Ka constant in a titration experiment.
  • #1
dagg3r
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Chemistry Buffers Theory !

hi guys need some help with buffers heh

anyways my query is say i have a buffer system, then i add say a strong base or a strong acid, then the ph changes, what's a general statement i can make for these observations regarding the h+ ion concentration and stuff. I know that if i have the buffer, and i add hcl the h+ ions will be consumed by the conjugate base in the buffer and if we add heaps of acid the ph will decrease cos of too much h+ just an opinion anyone care to help me out :)

and anyone also care to give me reasons and differences why ka value experimentally is different to the literally value? when doing a titration of Nh3 against HCl. thanks
 
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  • #2
any ideas the best i can prob come up with is errors with equipment LOL
 
  • #3


Hi there,

A buffer is a solution that helps to maintain a stable pH even when small amounts of acid or base are added. This is due to the presence of a weak acid and its conjugate base in the solution. When a strong acid or base is added, it will react with the weak acid or base in the buffer, preventing a large change in pH.

In terms of the H+ ion concentration, when a strong base is added to a buffer, it will consume some of the H+ ions present in the solution, resulting in a slight decrease in pH. On the other hand, when a strong acid is added, it will react with the conjugate base in the buffer, producing more H+ ions and causing a slight increase in pH. Overall, the buffer system helps to minimize the changes in pH caused by the addition of strong acids or bases.

As for the differences between the experimentally determined Ka value and the theoretical value, there are a few factors that can contribute to this. One reason could be experimental error, such as inaccurate measurements or variations in the reaction conditions. Another factor could be the presence of impurities in the chemicals used, which can affect the reaction and lead to different results. It's also important to note that theoretical values are based on ideal conditions, which may not always be achievable in a laboratory setting.
 

1. What is a buffer in chemistry?

A buffer in chemistry is a solution that helps maintain a stable pH level when an acid or base is added to it. It consists of a weak acid and its conjugate base, or a weak base and its conjugate acid.

2. How does a buffer work?

A buffer works by utilizing the principles of Le Chatelier's principle and the equilibrium constant to resist changes in pH. When an acid is added, the buffer's weak base component reacts with it to neutralize the excess hydrogen ions. Similarly, when a base is added, the buffer's weak acid component reacts with it to neutralize the excess hydroxide ions.

3. What is the Henderson-Hasselbalch equation?

The Henderson-Hasselbalch equation is a mathematical formula used to calculate the pH of a buffer solution. It is written as pH = pKa + log([conjugate base]/[weak acid]), where pKa is the negative logarithm of the acid dissociation constant. This equation allows us to determine the effectiveness of a buffer in maintaining a stable pH.

4. How do you prepare a buffer solution?

To prepare a buffer solution, you will need to mix a weak acid or weak base with its conjugate base or conjugate acid. The components should be present in a 1:1 ratio and should be dissolved in a solvent such as water. The concentrations of the components will depend on the desired pH of the buffer solution.

5. What is the importance of buffers in biological systems?

Buffers are crucial in biological systems because they help maintain a constant pH, which is essential for many biochemical processes to occur. Our body, for example, has many buffer systems to regulate the pH of our blood and prevent any drastic changes that could be harmful to our cells. Without buffers, these systems would not be able to function properly, and our bodies would not be able to maintain homeostasis.

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