From `B_(2)H_(6)`, all the following can be prepared except

Options

A. `H_(3)BO_(3)`
B. `B_(2)O_(3)`
C. `B_(2)(CH_(3))_(6)`
D. `NaBH_(4)`

Answer

To solve the question regarding which compound cannot be prepared from \( B_2H_6 \) (diborane), we will analyze each option provided and determine their feasibility of preparation from diborane.

### Step-by-Step Solution:

1. **Understanding Diborane (\( B_2H_6 \))**:
- Diborane is a compound of boron and hydrogen, known for its ability to react with various substances to form different boron-containing compounds.

2. **Option 1: Boric Acid (\( H_3BO_3 \))**:
- Diborane can be hydrolyzed to form boric acid:
\[ B_2H_6 + 6H_2O \rightarrow 2H_3BO_3 + 6H_2 \]
- This reaction shows that boric acid can indeed be prepared from diborane.

3. **Option 2: Boron Trioxide (\( B_2O_3 \))**:
- Diborane can also react with oxygen to form boron trioxide:
\[ B_2H_6 + 3O_2 \rightarrow B_2O_3 + 3H_2O \]
- This indicates that boron trioxide can also be prepared from diborane.

4. **Option 3: \( B_2CH_6 \)**:
- The compound \( B_2CH_6 \) does not exist as a stable compound. The reaction of diborane with methanol (\( CH_3OH \)) leads to the formation of trimethyl borate (\( B(OCH_3)_3 \)) and hydrogen:
\[ B_2H_6 + 3CH_3OH \rightarrow 2B(OCH_3)_3 + 3H_2 \]
- Therefore, \( B_2CH_6 \) cannot be prepared from diborane.

5. **Option 4: Sodium Borohydride (\( NaBH_4 \))**:
- Sodium borohydride can be synthesized from diborane by reacting it with sodium hydride:
\[ NaH + B_2H_6 \rightarrow NaBH_4 \]
- This shows that sodium borohydride can also be prepared from diborane.

### Conclusion:
From the analysis above, the compound that cannot be prepared from \( B_2H_6 \) is \( B_2CH_6 \). Thus, the answer is:

**Answer: \( B_2CH_6 \)**