Question

ION-SELECTIVE ELECTRODE POTENTIOMETRY

The fluoride ion concentration in a mouthwash sample was determined using ISE. Potentials of standard solutions containing fluoride ion are given in Table 1. The sample for ISE was prepared by pipetting 10.00 mL of the original mouthwash and diluting to 250.00 mL. The potential of the sample was recorded as –0.015 V.

Table 1. Measurement of ISE potential of standard solutions containing fluoride ion.

[F-], M	Potential, mV
5.0 x 10-6	0.077
5.0 x 10-5	0.020
5.0 x 10-4	-0.037
5.0 x 10-3	-0.093
5.0 x 10-2	-0.150

Calculate the concentration of the original mouthwash sample. SHOW ALL YOUR CALCULATIONS!

Answer 1