Hydrogen sulfide is a colorless gas (b.p.-60.2)that smells like rotten eggs. (The odor of rotten eggs actually does come from hydrogen sulfide, which is formed by the bacterial decomposition of sulfur-containing proteins.) Hydrogen sulfur is a highly toxic substance that, like hydrogen cyanide, attacks respiratory enzymes. It is a very weak diprotic acid (see Table 16.3). In basic solution, H2S is a reducing agent. For Table 22.3 Common compounds of sulfur