The pH is a measure of the acidity or alkalinity of an aqueous solution. The pH scale ranges from 0 to 14, with 7 being neutral, values below 7 indicating acidity, and those above 7 indicating alkalinity. A Ph Calibration Solution of less than 4.0 or greater than 9.0 is an indication that the sample may have been contaminated or contains substances that interfere with the test...