Lithium hydride reacts with aluminum chloride to form a complex. The geometry of the complex and the ligand present in the complex is

Options

A. Octahedral, chloride
B. Tetrahedral, hydride
C. Octahedral, bridging chloride
D. Tetrahedral, Chloride and hydride

Answer

To solve the question regarding the reaction of lithium hydride (LiH) with aluminum chloride (AlCl3) and to determine the geometry of the resulting complex and the ligands present, we can follow these steps:

### Step 1: Write the Reaction
The first step is to write the balanced chemical equation for the reaction between lithium hydride and aluminum chloride.

**Reaction:**
\[ \text{LiH} + \text{AlCl}_3 \rightarrow \text{LiAlH}_4 + \text{LiCl} \]

### Step 2: Identify the Complex Formed
From the balanced equation, we can see that the complex formed is lithium tetrahydridoaluminate, which is represented as LiAlH4.

### Step 3: Analyze the Structure of the Complex
Now, we need to analyze the structure of LiAlH4. The aluminum (Al) is surrounded by four hydride (H) ligands.

### Step 4: Determine the Geometry
To determine the geometry of the complex, we can use the VSEPR (Valence Shell Electron Pair Repulsion) theory. Since there are four hydride ligands around the aluminum, the geometry is tetrahedral.

### Step 5: Identify the Ligands
In this complex, the ligands present are the hydride ions (H⁻). There are no chloride ions in the complex itself; they are present in the reaction as a product (LiCl).

### Final Answer
Thus, the geometry of the complex LiAlH4 is tetrahedral, and the ligand present in the complex is hydride.

### Summary of the Answer
- Geometry of the complex: **Tetrahedral**
- Ligand present in the complex: **Hydride**

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