What is the chemical formula for hydrogen sulfide gas?

The chemical formula for hydrogen sulfide gas is represented as H2S. This formula indicates that each molecule of hydrogen sulfide contains two hydrogen atoms bonded to one sulfur atom.

To break it down further, hydrogen sulfide consists of one sulfur atom, which is a chalcogen and commonly can form two bonds due to its valence of 2, and two hydrogen atoms, each providing one bond. The combination of these atoms forms the simple molecular structure of hydrogen sulfide, which is known for its characteristic odor of rotten eggs.

The incorrect options either suggest an incorrect ratio of hydrogen to sulfur or misrepresent the molecular structure. For example, H2S2 implies an incorrect stoichiometry that would suggest there are twice as many sulfur atoms as in hydrogen sulfide, which does not reflect the known molecular composition of this compound. Similarly, HS and HS2 do not correctly represent the number of hydrogen and sulfur atoms bonded in the molecule either.

Thus, H2S accurately describes the chemical make-up of hydrogen sulfide, aligning with established chemical nomenclature rules.