In the reaction: `BF_(3)+3LiBH_(4)to3LiF+X, X` is

Options

A. `B_(4)H_(10)`
B. `B_(2)H_(6)`
C. `BH_(3)`
D. `B_(3)H_(8)`

Answer

To solve the question regarding the reaction of BF3 with lithium boron hydride (LiBH4), we need to identify the product X formed in the reaction. Let's break it down step by step.

### Step 1: Write the given reaction
The reaction is given as:
\[ \text{BF}_3 + 3 \text{LiBH}_4 \rightarrow 3 \text{LiF} + X \]

### Step 2: Identify the reactants and products
- **Reactants**: Boron trifluoride (BF3) and lithium boron hydride (LiBH4).
- **Products**: Lithium fluoride (LiF) and an unknown product X.

### Step 3: Analyze the products
From the reaction, we know that 3 moles of lithium fluoride (LiF) are produced. We need to determine what X could be.

### Step 4: Balance the reaction
1. **Fluorine atoms**: There are 3 fluorine atoms in BF3, which balance with 3 LiF.
2. **Boron atoms**:
- BF3 has 1 boron atom.
- Each LiBH4 has 1 boron atom, and since there are 3 LiBH4, that gives us 3 boron atoms.
- Total boron from reactants = 1 (from BF3) + 3 (from 3 LiBH4) = 4 boron atoms.
- Therefore, the product must contain 4 boron atoms.

### Step 5: Determine the possible products
The possible products given in the options are:
1. B4H10
2. B2H6
3. BH3
4. B3H8

Since we have 4 boron atoms in total, we need to find a product that contains 4 boron atoms.

### Step 6: Identify the correct product
- **B4H10**: This contains 4 boron atoms and is a valid product.
- **B2H6**: This contains 2 boron atoms, so it cannot be the product.
- **BH3**: This contains 1 boron atom, so it cannot be the product.
- **B3H8**: This contains 3 boron atoms, so it cannot be the product.

### Conclusion
The only valid product that contains 4 boron atoms is B4H10. Thus, we conclude that:
\[ X = \text{B}_4\text{H}_{10} \]

### Final Answer
The answer is option 1: B4H10.