Question

Pure water has a hydrogen ion concentration of 1 x 10 (-7) M and a ph of 7. A student measures a basic solution and finds that it has a hydrogen ion (H+) concentration of 1 x 10(-3). Explain why the student must have made an error in her measurement.

Answer 1

The student must have made an error in her measurement in the concentration of hydrogen ion in the basic solution given. From her measurement, the concentration is 1 × 10−3 M. If we calculate the pH, we get:

pH = -log ( 1 × 10−3) = 3

A pH of 3 does not signifies a basic solution it is in the acidic range. So, the measurement is wrong.