1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Potentiometry lab question

  1. Nov 22, 2007 #1
    In this potentiometry lab, serial dilutions were made from stock 0.1M solution of NaF that ranged from 1E-2M to 1E-6M. Then these solutions were measured with a fluoride ion-selective electrode for response. The question is why does the potential become constant when the concentration of NaF is below 1x10^-6 M

    From the book, I found out that the fluoride electrode is made with a single crystal of an insoluble pure rare-earth fluoride such as LaF3, NdF3 or PrF3 and when the concentration of NaF is below 10^-6, the lanthanum fluroride (LaF3) contributes more fluoride ion to the solution than is originally present. so thats why the potential is constant. I don't really get this... when it says the potential is constant, does that mean the potential is equal to 0? if it is equal to 0, aren't there still some F- from the LaF3 that can contribute to the potential?
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted