Figure 3. EDX spectra (a), elemental composition (b), SEM image (c) and elemental mapping (d) of deposits on the surface of copper, exposed in concentrated H2SO4

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