FLUORIDE ION ELECTRODE
p
Electrode Properties
E (millivolts)
0.00010 M F-
66.7
0.00035 M F-
37.0
0.00060 M F-
22.8
0.00085 M F-
14.2
0.001 M F-
9.00
0.01 M F-
-49.7
Electrode Slope,
S
-58.9
Method of Standard Addition
Potential of control solution:
-0.90 mV
Potential of control solution plus standard addition
-14.1 mV
Measured concentration of F- in diluted control
0.00145 M
Measured concentration of F- in undiluted control
0.00289 M
Unknown Sample
Identify the commercial product you’ve analyzed and include the reported concentration of F-
from the packaging:
Listerine Mouthwash, Sodium Fluoride 0.02% (0.01% w/v fluoride ion)
Unknown Sample Data Table (include units with your answers):
Potential of commercial product
32.9 mV
Potential of commercial product plus standard addition
40.4 mV
Measured concentration of F- in diluted commercial product
0.00283 M
Measured concentration of F- in undiluted commercial
product
0.00496 M
