What is the pH of a 0.01 M solution of the strong acid #HClO_4#, perchloric acid?

1 Answer
May 11, 2016

Answer:

#pH=-log_(10)[H_3O^+]=-log_(10)(10^-2) = 2#

Explanation:

This question may be answered without a calculator. We are asked to take the logarithm to the #"base 10"# of #10^(-2)#, which is clearly #-2#, why? We are then asked to give the negative value of that logarithm.

Perchloric acid is exceptionally strong, and undergoes complete ionization in water:

#HClO_4(aq) + H_2O(aq) rarr H_3O^+ + ClO_4^-#

Now not only do you have to learn how to take logarithms, you also have to learn how to take antilogarithms, if asked to find concentrations given a #pH#, see here .