A chemist adds a chemical to pure water and there is a 100 fold increase in the concentration of hydrogen ions.What is the best approximation of the new pH value?
A)0
B)5
C)7
D)9

Question

Quizplus · Accepted Answer

The pH of pure water is 7. A 100-fold increase in hydrogen ion concentration means the concentration increases by 10^2, which decreases the pH by 2 units (since pH = -log[H+]). Therefore, the new pH is approximately 5.

A Chemist Adds a Chemical to Pure Water and There