[TheBucketMan0517]

Hello, I’m a senior high school student hoping to study Chemistry in the fall and I’m completing a “research project” to determine the standard reduction potentials of electrochemical cells. More specifically:
Fe (2+), Sn (2+), Zn (2+), Copper (2+), & Mg(2+).

I’m using the Iron as a “constant” to determine the reduction potentials of the other 4 (since I can’t afford a calomel electrode and my school doesn’t have one) but what I’m wondering is if the solution (specifically the anion) the metal strip of a Voltaic cell matters as long as the cation is 2+. My Penn State professor for gen chem 2 stated that it didn’t matter but my High School chemistry teacher wants me to verify that and I’m sort of lost.

Please help I’m making myself go crazy because I cant find the answer.

[Borek]

what I’m wondering is if the solution (specifically the anion) the metal strip of a Voltaic cell matters as long as the cation is 2+

Honestly, I have no idea what you are asking.

[TheBucketMan0517]

I should have prefaced it with a picture of a Voltaic cell. Does the 1M solution which the metal strip rests in matter as long as the cation is the same metal as the strip?

[Hunter2]

If you use different metal, then you get electro chemical reaction of the metal with the Cations in solution. If the metal is more ignoble then it will be dissolved and the Cations of the solution will precipitate.

[Borek]

Does the 1M solution which the metal strip rests in matter as long as the cation is the same metal as the strip?

No, but yes.

If you can guarantee the activity of the free metal is 1 - doesn't matter what the other components are (at least long as they don't react separately).

Trick is, many anions have quite strong complexing properties, so some of the cation will be complexed and you won't know its concentration.

Also, ionic strength of the solution will depend on the charge of the counterion, so it gets difficult to make sure the activity of the cation is exactly 1.

Sadly, plenty of fine prints which make the situation complicated and difficult to control.

A lot depends on how accurate your measurements need to be though, some of the effects can be ignored, some can be estimated.