If given a pH of 2.57, how do you find the pKa?

1 Answer
Jan 30, 2016

You can find #[H_3O^+]#, but you cannot find #pK_a# with the given information.

Explanation:

If #pH# #=# #2.57#, then (by definition), #[H_3O^+]# #=# #10^(-2.57)# #mol*L^-1#. We have no handle on the concentration of the acid that gave rise to this concentration of hydronium ion.