The Dissolution Reaction and Attack of Beryllium by HF, HCl, and H[sub 2]SO[sub 4]

Abstract

Beryllium reactions with the three acids, which are expected to react as follows: Be + 2HF yields BeF/sub 2/ + H/sub 2/, Be + 2HCl yields BeCl/sub 2/ + H/sub 2/, and Be + H/sub 2/SO/sub 4/ yields yields BeSO/sub 4/ + H/sub 2/, were checked by dissolving a weighed amount of the metal in the acids and measuring the volume of hydrogen evolved. Although the quantitative reactions were quite similar, the attack of the metallic surface by HCl differed from that by the other two acids. A polished surface of Be, subjected to the action of HF or H/sub 2/SO/sub 4/ remained smooth, as if polished, even after a longer etching time. However, high magnifications revealed some structure. Contrary to this, the reaction with HCl (about 0.5N) was strongly localized since the structure of the metal appeared clearly with striations across the grains. When Be was dissolved in HCl at concentrations lower than 0.5N. a black deposit covered the metal which then separated from the latter and turned the whole solution black. No formation of a black deposit was observed in concentrations higher than 0.5N HCl and no blackening of the acids could be observed in any concentration ofmore » HF and H/sub 2/SO/sub 4/. However, formation of a black deposit and hence, disintegration of Be was also observed in HClO/sub 4/ at about 0.3N and in HBr at about lN. (P.C.H.)« less