Figure 1. Black deposit on the surface of copper, which was formed during copper dissolution in concentrated sulfuric acid

From

Copper Dissoliution in Concentrated Sulfuric Acid

A. Sulcius, E. Griskonis, N. Zmuidzinaviciene

World Journal of Chemical Education. 2019, 7(3), 196-202 doi:10.12691/wjce-7-3-2