No, lithium hydride is not soluble in water; instead, it reacts vigorously with it.
Understanding Lithium Hydride's Interaction with Water
Lithium hydride (LiH) is an alkali metal hydride that is a colorless solid, though commercial samples often appear grey. It is characterized as a salt-like (ionic) hydride, which contributes to its high melting point and distinct reactivity profile.
Reactivity, Not Solubility, with Water
When lithium hydride encounters water, it does not simply dissolve to form a solution. Instead, a strong chemical reaction occurs. Water is considered a protic solvent, and lithium hydride is known to be reactive with all protic solvents. This reaction is:
LiH (s) + H₂O (l) → LiOH (aq) + H₂ (g)
In this reaction:
- Lithium hydroxide (LiOH) is produced, which is a strong base.
- Hydrogen gas (H₂) is released. This gas is highly flammable and can ignite, especially given the exothermic nature of the reaction (it releases heat).
The vigor of this reaction means that lithium hydride is incompatible with water and must be handled in dry, inert conditions to prevent hazardous situations.
Key Characteristics of Lithium Hydride
To further clarify its nature, here's a summary of lithium hydride's relevant properties:
| Characteristic | Description |
|---|---|
| Appearance | Colorless solid; commercial samples often grey |
| Chemical Nature | Salt-like (ionic) hydride |
| Melting Point | High |
| Solubility in Water | Not soluble; undergoes vigorous chemical reaction |
| Reactivity | Highly reactive with water and other protic solvents |
| Reaction Products (with water) | Lithium hydroxide (LiOH) and hydrogen gas (H₂) |
Safety Considerations
Due to its extreme reactivity with water and the production of flammable hydrogen gas, lithium hydride must be handled with great care. It should be stored in airtight containers, away from moisture and acids, and in a well-ventilated area. Working with lithium hydride typically requires protective equipment and a dry, inert atmosphere (such as argon or nitrogen) to avoid any contact with water or humidity.
For more information on chemical reactivity and safety, you can refer to reputable chemical databases such as PubChem.
