Just like in hard water stains this layer may be the insoluble salt and other impurities that were inhibiting the conductivity.

Lead thus can dissolve in acids, but this is often impossible due to specific problems (such as the formation of insoluble salts).

Calcium carbonate is such an insoluble salt.

When mixed, one member from each soluble salt will find each other and form an insoluble salt which precipitates itself.

This technique is used for ionic species that form insoluble salts and will deposit on or near the anodic, working electrode during deposition.

The reaction is driven toward products by mass action due to the precipitation of the insoluble salt, which removes it from the equilibrium expression.

It usually takes place when the concentration of dissolved ions exceeds the solubility limit and forms an insoluble salt.

The alcohol (S)-enantiomer forms an insoluble diastereomeric salt with the mandelic acid and can be filtered from the solution.

Soluble salts continue on down, but insoluble salts are left behind in the oxidised zone where they form.

They are able to bind otherwise insoluble salts into organic solvents.