Hydrogen gas is a highly reactive element under specific conditions. Based on available information, it reacts with a wide range of other elements and compounds.
Hydrogen gas reacts with almost all metals and nonmetals under high temperatures. It also serves as a reducing agent, reacting with the oxides and salts of many metals.
Reactions with Elements
Hydrogen exhibits reactivity with most other elements, typically requiring energy input like heat to initiate the reaction.
- Metals: Hydrogen reacts with almost all metals. These reactions usually occur at high temperatures. The resulting compounds are often called metal hydrides.
- Nonmetals: Similarly, hydrogen reacts with almost all nonmetals. These reactions also generally require high temperatures. Examples include reactions with oxygen (forming water), nitrogen (forming ammonia), and halogens (forming hydrogen halides).
Reactions as a Reducing Agent
Beyond reacting directly with elements, hydrogen is known for its ability to remove oxygen from compounds (reduction).
- Metal Oxides: At elevated temperatures and pressures, hydrogen can reduce the oxides of most metals. This reaction removes the oxygen from the metal oxide, yielding the pure metal and water.
- Example: $\text{CuO} + \text{H}_2 \rightarrow \text{Cu} + \text{H}_2\text{O}$ (Requires heating)
- Metallic Salts: Hydrogen can also reduce many metallic salts under elevated temperatures and pressures, producing the corresponding metal.
Summary of Hydrogen Reactions
Here is a simple overview of the types of substances hydrogen reacts with based on the information provided:
| Reactant Category | Specific Substance Type | Conditions Required | Product Type(s) |
|---|---|---|---|
| Elements | Almost all metals | High temperatures | Metal hydrides |
| Elements | Almost all nonmetals | High temperatures | Binary compounds (e.g., $\text{H}_2\text{O}$, $\text{NH}_3$, $\text{HCl}$) |
| Compounds | Oxides of most metals | Elevated temperatures/pressures | Metal + Water |
| Compounds | Many metallic salts | Elevated temperatures/pressures | Metal + Other products |
In summary, hydrogen gas is versatile in its reactivity, participating in direct combination reactions with most elements and acting as a powerful reducing agent for many metal compounds under suitable conditions.
