changing pH

[princessdiana97]

Hi I just need to know if there was a standard concentration for the acid and base that I am going to use to change the pH of the media that I am making for bacteria? I am using NaOH and H2SO4. THanks

[iansmith]

there not standard but you have to be carefull with the contrentration you will use. for instance in our lab to adjust the pH we use a 5 M NaOH solution. We also have HEPES buffer in our medium. This works works well because you do not have to had a large volume to change the pH. If you do not have buffers in your medium, a lower concentration migth be more suited. If your acid or base use for adjusting your pH is too low you will increase your volume significantly and might pass the targeted volume. If it is too strong you have problem adjusting precisely but you can always dilute high concentration of a strong acid/base in a becker to have a lower concentration.

In our we don't use H2SO4, we usually use HCl at around a 5 M concentration. Other acid or base we usually use a 1 M concentration.