[Jfalken]

So, if I have access to MQ-water and I want to slightly acidify it (let's say to pH 5.3) and I have a 24% solution of Acetic acid at hand.
How much of the Acetic acid to I need to get a 500mL water phase with a pH of 5.3?
MQ-water pH = 7.

How would I do the calculation?

[chenbeier]

Use the Formula of weak acids.

https://www.thoughtco.com/calculating-ph-of-a-weak-acid-problem-609589