How Does a pH Meter Measure H+ Concentration?: How Does a pH Meter Measure H+ Concentration?
The pH meter has two electrodes in one tube, glass and reference electrode. A saturated KCL and HCL solution is contained in a tube which is inside of an outer tube that will have contact with the solution to be measured. This outer tube has a double glass bulb with NA+ which makes an ion specific electrode. When measuring the pH of a solution, a salt bridge forms. The NA+ ion, not H+, crosses the glass membrane of the pH electrode and allows for a change in free energy which is measured by the pH meter as the concentration of H+. Calibrating a pH Meter: Calibrating a pH Meter Make sure the meter is in pH mode For a 3 point calibration, use high pH (–), pH 7.0 and low (-.0) solution Before calibration, rinse probe thoroughly with de-ionized water or a rinse solution Immerse the end of the probe completely in the calibration solution Stir the probe gently to create a homogenous sample Measuring the pH of a Solution: Measuring the pH of a Solution Always rinse electrodes with de-ionized
