Brass corrosion – dezincification in hydrochloric acid

Brass is among the utility metals for daily life. We present an easy corrosion experiment for demonstration in high school or first-year undergraduate studies. Almost any kind of brass can be dezincified in 1 m hydrochloric acid. Copper as the noble component remains as salmon pink coating on the workpiece while zinc and lead, the latter being a frequent minor alloying component of brass, are dissolved. Lead can be detected as PbS (in-situ generation of H2S from a splinter of FeS or as PbI2 using KI). Zinc can be analyzed as Rinmann’s green or via a microchemical drop reaction with dithizone.