Creating Buffers: Salt or Acid/Base Pair?

In summary, a buffer can be created with just a salt or a salt and its conjugate acid/base. It is not necessary for both the salt and conjugate acid/base to be present together to create a buffer. The key is to have a conjugate pair, regardless of how it is obtained in the solution. This can be achieved by starting with an acid and a salt, partially neutralizing an acid with a base, or acidifying a salt with an acid.
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i_love_science
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Does there have to be both a salt and the conjugate acid/base of the anion/cation to create a buffer? Or can just a salt (e.g. ammonium formate) be a buffer?

Does a buffer require a salt that contains the same conjugate base as the acid, or not necessarily?

Thanks.
 
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You need a conjugate pair, how you got it in the solution doesn't matter. You can start with an acid and a salt, you can start with the acid and partially neutralize it with some other base, you can start with just the salt and acidify it with some other acid.
 
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1. What is a buffer?

A buffer is a solution that resists changes in pH when small amounts of acid or base are added. It is made up of a weak acid and its conjugate base, or a weak base and its conjugate acid.

2. Why are buffers important in scientific experiments?

Buffers are important because they help maintain a stable pH in a solution, which is crucial for many biological and chemical reactions to occur. They also prevent sudden changes in pH that could damage cells or alter the outcome of an experiment.

3. How do you create a buffer using a salt?

To create a buffer using a salt, you need to mix a weak acid with its conjugate base, or a weak base with its conjugate acid, and add a salt that contains the conjugate of the weak acid or base. The salt will react with any added acid or base, preventing a significant change in pH.

4. Can you use any salt to create a buffer?

No, not all salts can be used to create a buffer. The salt must contain the conjugate of the weak acid or base in the buffer solution. For example, if you are creating a buffer with acetic acid and sodium acetate, you cannot use sodium chloride as the salt because it does not contain the conjugate base of acetic acid.

5. How do you choose whether to use a salt or an acid/base pair to create a buffer?

The choice between using a salt or an acid/base pair to create a buffer depends on the desired pH of the solution. If the desired pH is close to the pKa of the weak acid or base, then an acid/base pair would be more effective. If the desired pH is further from the pKa, then a salt would be a better choice.

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