Calomel Electrode - Negative PD

[bmp8501]

After constructing a Calomel Reference Electrode, using; Hg + Hg2Cl2, few issues;

1. Negative PD (~ -0.2 V)

2. PD keep dropping and eventually drops to zero (within 24 hrs)

The standard reduction potential of calomel electrode is supposed to be +0.243V.

any thoughts?

 

[dennisbernal91z]

I am trying to do the same thing. Are you sure you have your leads the right way? You would have +0.2V if they were swapped.

I was getting -0.500V until I noticed that my silver pin was touching the Hg/Hg2Cl2 mixture and messing up the redox reaction.

How are you making the Hg calomel "paste"? I have seen both a paste and a method with both being seperate. I am also making mine very small to fit in a medical instrument so packaging is an issue for me.

Fill me in with more details, maybe we can help eachother out.