What happens when `H_(2)` is passed over lithium at 1073K?

Options

A. Covalent lithium hydride is formed
B. Coloured complex is formed
C. Ionic lithium hydride is formed
D. No reaction

Explanation

To solve the question of what happens when hydrogen gas (H₂) is passed over lithium (Li) at a temperature of 1073 K, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this scenario are lithium (Li) and hydrogen gas (H₂).

2. **Understand the Conditions**: The reaction occurs at a high temperature of 1073 K. This elevated temperature is significant as it can facilitate the reaction between lithium and hydrogen.

3. **Determine the Type of Reaction**: Lithium is an alkali metal, which typically forms ionic compounds. Hydrogen, being a non-metal, can react with metals to form hydrides. Therefore, we expect an ionic hydride to form.

4. **Write the Chemical Reaction**:
- The reaction can be represented as:
\[ 2 \text{Li} + \text{H}_2 \rightarrow 2 \text{LiH} \]
- Here, lithium reacts with hydrogen gas to form lithium hydride (LiH).

5. **Consider the Properties of the Product**: Lithium hydride (LiH) is known to be an ionic compound. It has a high melting point due to the strong ionic bonds between lithium ions (Li⁺) and hydride ions (H⁻).

6. **Conclusion**: When hydrogen gas is passed over lithium at 1073 K, lithium hydride (LiH) is formed as a product.

### Final Answer:
When hydrogen is passed over lithium at 1073 K, ionic lithium hydride (LiH) is formed.

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