Which of the following statement is not true regarding `B_(2)H_(6)` ?

Options

A. It reacts with `NaH` to form `NaBH_(4)`
B. It is inflammable gas
C. It does not contain four equal `B - H` bonds
D. it reacts with Lewis base to form adduct

Answer

To determine which statement is not true regarding diborane (B₂H₆), we will analyze each option provided.

### Step-by-Step Solution:

1. **Analyze Option A: "It reacts with NaH to form NaBH₄."**
- Diborane (B₂H₆) can react with sodium hydride (NaH) to produce sodium borohydride (NaBH₄). The reaction can be represented as:
\[ B_2H_6 + 2 NaH \rightarrow 2 NaBH_4 \]
- This statement is true.

2. **Analyze Option B: "It is an inflammable gas."**
- Diborane is known to be highly volatile and flammable. It can ignite spontaneously in air. Therefore, this statement is also true.

3. **Analyze Option C: "It does not contain 4 equal BH bonds."**
- The structure of diborane (B₂H₆) consists of two boron atoms and six hydrogen atoms. It has a unique bonding arrangement where there are two bridging hydrogen atoms and four terminal hydrogen atoms. The bonding involves 3-center 2-electron bonds, which means that not all bonds are equivalent. Thus, the statement that it does not contain 4 equal BH bonds is true.

4. **Analyze Option D: "It reacts with Lewis acid to form an adduct."**
- Diborane can react with Lewis acids, such as ammonia (NH₃), to form an adduct. The reaction can be represented as:
\[ B_2H_6 + NH_3 \rightarrow [B_2H_5(NH_3)] \]
- This statement is also true.

### Conclusion:
After analyzing all the options, the statement that is not true is **Option C: "It does not contain 4 equal BH bonds."** This is incorrect because diborane does not have 4 equal BH bonds due to its unique bonding structure.

### Final Answer:
The statement that is not true regarding B₂H₆ is **Option C: "It does not contain 4 equal BH bonds."**