[nimk]

Let's say you have to create a buffer solution using KH₂PO₄ 0.1 M (salt). Then, you have to add a strong base or acid to reach the desired pH. How do I determine if I need to use a strong or weak acid/base? Let's say the desired pH is 8 and the pH of the buffer is 3.56  (made up numbers). Please explain thoroughly.

[Borek]

Pretty simple: adding an acid always lowers pH, adding a base always makes pH higher.

[nimk]

What I mean is how do I determine if i should use a strong or weak acid/base, keeping in mind that the pKa of the buffer is 7.2

[nimk]

Pretty simple: adding an acid always lowers pH, adding a base always makes pH higher.

What I mean is how do I determine if i should use a strong or weak acid/base, keeping in mind that there's a buffer and the pKa of the buffer is 7.2

[Borek]

In the case you listed - you already started with a weak acid, now use a strong base to neutralize it partially.

Do you understand what is a base and what is an acid in the buffer solution?

Let's say you prepared a buffer solution mixing acetic acid and NaOH. What is the acid in this buffer, and what is the base in this buffer solution?