bottles with samples of liquid, pH Meter and Probe, pH Buffer Solution (Standardizer), Stirring Rod, Distilled Water in Wash Bottle, Lab Jack
pH Meter and Probe, container, beaker, Stirring Rod, Distilled Water in Wash Bottle, Lab Jack

 

Code Number: 10B10.20

Demo Title: pH of Common Liquids

Condition: Good

Principle: Acid - Base Measurements

Area of Study: Chemistry and Physics

Equipment: 

pH Meter and Probe, pH Buffer Solution (Standardizer), Stirring Rod, Distilled Water in Wash Bottle, Lab Jack, Video Camera and Power Supply, Daiquiri (Calvert will supply this), Draino, Tomato Juice, Beer, Lemon Juice, Lime Juice, Mountain Dew, Tap Water and Distilled Water, Ethyl Alcohol, Milk.

Procedure:

Assemble the apparatus as shown. Check the batteries in the pH meter. Wash the probe tip with distilled water and then lower it into the buffer solution and recalibrate. After testing each liquid the probe must be rinsed with distilled water to maintain accuracy. Approximate pH ranges are as follows: 

Daiquiri                      2.7 to 2.9

Draino                        8.7 to 8.8

Tomato Juice             4.5 to 4.6

Beer (Bud Light)       4.55 to 4.65

Lemon Juice               2.5 to 2.6

Mountain Dew            3.3 to 3.4

Tap Water                  8.5 to 8.6

Distilled Water          6.95 to 7.05

Milk                             6.6 to 6.7

Ethyl Alcohol              6.7 to 6.9

pH Buffer                         7.0

Store the pH probe with a few drops of distilled water in the protective cap as the probe will be destroyed if it remains dry for extended periods.

References:

  • Curt Suplee, "Seeking balance: pH", Everyday Science Explained, National Geographic, p. 150.
  • Herb Strongin, “Investigating Acids and Bases Using Litmus Paper“, Science on a Shoestring, p. 35. 
  • Borislaw Bilash II, “Indicators Make the pH Scale Colorful“, A Demo A Day – A Year of Physical Science Demonstrations, p. 182.