In polarography, what is the minimum voltage needed to cause reduction of metal ions called?

The minimum voltage needed to cause the reduction of metal ions in polarography is referred to as the decomposition potential. This term specifically describes the threshold voltage at which the reduction process begins, meaning that it is the point where the applied potential is sufficient to overcome the energy barrier for the reduction of metal ions in solution.

Decomposition potential is critical in electrochemistry because it helps in determining the onset of electrochemical reactions involving metal ions. Understanding this potential is vital in various applications, such as sensing and analytical chemistry, where precise control over electrochemical processes is necessary for accurate measurements.

The other terms, while related to electrochemical concepts, do not specifically define the minimum voltage for reduction. The half-wave potential relates to the potential at which half of the limiting current is observed, the isopotential point does not have a standardized meaning in polarographic terms, and polarization potential refers to the additional potential required to maintain a steady current during an electrochemical reaction, rather than being a specific threshold for reduction.