chenbeier

It is the limit of your device and probably also the material of your quarz cuvette. It is in UV value.

Boil it until all water is gone. Or put it in a ball and wait some day until the water is vaporized slowly. Result you would get nice crystalls of copper chloride

What do you want purify, if there is no knowledge what containing the water.: Poisson elements, germs, herbs, etc.??? Boil the water=> kill bionic. Then filter through charcoal sand. To remove dangerous ions destill the water. OR Go in a supermarket and buy canned or bottled water.

It is cathode - anode normally. But check the Nernst equation if the Logarithmen has a plus or minus and the quotient is log(Ox/Red) or log(Red/Ox). This change the value.

Then it is no Carbonate.

Should be possible, but you have to find a way to get a large surface.

Theoretical yes, but then you cannot make concrete. Everything has to be mixed with water.

Yes it does. Can find here: Handbook of Industrial Crystallization https://books.google.de/books?id=gJ7KNvbMtREC&pg=PA116&dq=solubility+NaCl+KCl&hl=de&sa=X&ved=0ahUKEwje-Lquu4bgAhUKDuwKHfe3DlQQ6AEILDAA#v=onepage&q=solubility NaCl KCl&f=false

Add some drop of acid to your precipitate, do you get bubbles?

Check here under number 6 https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Reactions/Oxidation_and_Reduction_Reactions/Oxidation_of_Organic_Molecules_by_KMnO4

Of course it can. In aromatic and aliphatic as well. One is oxidation with Permanganate to Carbonic acid and later change to Amid and use Hoffman reduction, Lossen or Curtius to Amin. And further reduction.

You want to clean electronical parts like the multiswitch on the picture? https://www.electrolube.com/blog/2018/05/22/how-to-clean-electrical-contacts/

Maybe try here: https://www.sigmaaldrich.com/catalog/search?term=malonic+acid&interface=All&N=0&mode=match partialmax&lang=de&region=DE&focus=product

A chemical institute, university or company should can buy it at several chemical supplier. Ferroin is a common redox indicator for determin iron II/III. We used it in our lab. Malonic acid should be also not so seldom. Substitutes I dont know. Other occilator reaction is the iodine clock. The chemicals maybe easier to obtain. https://en.wikipedia.org/wiki/Iodine_clock_reaction

Instead of the sodiumsalt try the silversalt. The equilbrium will go to the ester because of precipitation of AgBr. Or use Carboxylacid halid with sodiumalkanolate.