<span> hydrogen combines with
oxygen H2O</span>
<span>Hydrogen sulfide<span> <span>is the </span></span>chemical compound<span> <span>with the </span></span>formula <span>H<span>
2S</span></span>. It is a colorless gas<span> <span>with the characteristic foul odor of rotten </span></span>eggs<span>; it is heavier than air, very poisonous,
corrosive, flammable, and explosive; properties shared with the denser </span>hydrogen
chalcogenides</span>
