Hydrolith is

Options

A. `CaH_2`
B. `Ca(OH)_2`
C. `CaCO_3`
D. `CaSO_4`

Answer

To solve the question "Hydrolith is," we need to identify what hydrolith refers to and its significance in chemistry.

### Step-by-Step Solution:

1. **Identify the Substance**: The term "hydrolith" is often associated with calcium hydride (CaH₂). Calcium hydride is a chemical compound that is known for its ability to react with water to produce hydrogen gas.

2. **Chemical Composition**: Calcium hydride consists of calcium (Ca) and hydrogen (H) atoms. Its formula is CaH₂, indicating that one calcium atom is bonded to two hydrogen atoms.

3. **Reactivity with Water**: When calcium hydride comes into contact with water, it undergoes a hydrolysis reaction:
\[ \text{CaH}_2 + 2 \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{H}_2 \uparrow \]
This reaction produces calcium hydroxide (Ca(OH)₂) and hydrogen gas (H₂).

4. **Uses of Calcium Hydride**: Calcium hydride is primarily used as:
- A source of hydrogen gas, which can be utilized in various chemical reactions and processes.
- A reducing agent in chemical reactions, where it can donate electrons to other substances.

5. **Conclusion**: Based on the information gathered, we can conclude that hydrolith refers to calcium hydride, which is used as a source of hydrogen and as a reducing agent.

### Final Answer:
Hydrolith is calcium hydride (CaH₂), which serves as a source of hydrogen and a reducing agent.

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