How are pKa tables used?

1 Answer
Dec 22, 2016

The realtion between #K_A# and #pK_a# is #K_a = 10^(-pK_a)#. This value provides an essential constant for keeping track of concentration of #[H^+]# in solutions.

Explanation:

Much like the way that pH is written using the logarithm function to convert the actual #[H^+]# of a solution into a simpler value, so the #K_a# of an acid can be converted into a #pK_a# value.

Once you have the #K_a# value, the applications that can be made from #K_a# or #pK_a# (whichever you prefer to use), include the ability to determine the #[H^+]# in a solution of that acid, regardless of the concentration of the solution, or whether it is buffered for example.

#K_a# is an equilibrium constant, and as such is independent of the concentration of a solution. This makes it the best value for establishing the strength of that acid relative to others.