Acids & Bases Problem Set

Question 5. More pH Calculations

What is the pH of a 10 ^{- 10} M solution of HCl?

Although -log [10 ^{- 10}] = 10, common sense dictates that a very small amount of acid does not make a solution basic. Rather, such a small concentration of H ⁺ ions (10 ^{- 10} M) is far below the H ⁺ concentration for water (10 ^{- 7} M), thus the pH remains at 7.