Hydrogen gas (H₂) reacts with sulfur (S) to form hydrogen sulfide (H₂S), a colorless gas with a characteristic rotten egg smell. This reaction occurs at elevated temperatures, typically above 150°C.

Here's the balanced chemical equation:

H₂(g) + S(s) → H₂S(g)

Here's a breakdown of the reaction:

* Hydrogen gas is a diatomic molecule composed of two hydrogen atoms bonded together.

* Sulfur is a solid element at room temperature.

* Hydrogen sulfide is a gas with a strong, pungent odor. It is highly toxic and flammable.

The reaction is typically carried out in a closed container, as hydrogen sulfide is a volatile and potentially hazardous gas.

Note: The reaction between hydrogen and sulfur can also produce other compounds, such as polysulfides (H₂Sₓ), depending on the reaction conditions. However, the primary product is hydrogen sulfide.