Where do strong acids and bases fall on the pH scale?

1 Answer
Nov 9, 2015

Answer:

Acids are lower, bases are higher on the pH scale.

Explanation:

When determining the pH of a strong acid or base you should be given a concentration in molarity (moles/liter).

Since strong acids and bases completely disassociate in water you can take the #-log# of the molarity. For example, if you were asked to find the pH of a .058 M solution of #HCl# you would enter #-log(.058)#

You can see that it would have a pH of 1.23

You do the same thing for strong bases, but you have to remember that the answer that you will get will be #pOH#. To get the pH you simply subtract the #pOH# from 14.

For example, if you have a #NaOH# solution that has a molarity of .063 you take the #-log(.063)# and get a #pOH# of 1.20.

#14-1.20=12.79#

From that information you can see that acidic solutions have a lower pH and basic solutions have a higher pH.