Water can be purified by many ways. One way is distillation. A student distills water in a lab xperiment in which he is going to work with pH and acid/base properties. He pulls out a pH meter and discovers that his distilled water sample has an acidic pH reading. Knowing that neutral water should be neither acidic nor basic, the student assumes that the pH meter is not calibrated and after calibrating it again it reads a similar pH. What is the student doing wrong