A simple electrodeposition problem and the abundant knowledge it subserves to teach

Abstract

This paper presents a handful of electrochemical experiments related to one single system that opens up the way to teach a bunch of topics related to physical and inorganic chemistry, hence serving experience-oriented education of otherwise hard-to-understand fields. The key idea is the electrodeposition of metals from the same bath containing Cu2+ and Ni2+ ions onto electrodes that differ from each other either in size or position within the electrochemical cell. With the proper optimization of the current densities, pure Cu and a Ni-rich coating with shiny silver colour can be obtained on electrodes of large and small surface area, respectively. It will be explained in detail how to drive the discussion on the experiment so that the audience learns which processes can be treated as parallel ones (i.e. the deposition of two metals, Cu and Ni), the mass transport taking place in serial with the electrochemical reaction, and the occurrence of the mass transport limitation in an electrode process. Didactic aspects of the experiment are presented for both high school and undergraduate levels, and control experiments are also suggested to verify the conclusions achieved. Collateral topics of chemistry and materials science that can be brought up in connection with the experiment are also enumerated.