`Na_(2)[Be(OH)_(4)]` is formed when:

Options

A. `BeO` reacts with `NaOH` solution
B. Be reacts with `NaOH` solution
C. both correct
D. None is correct

Answer

To determine how `Na2[Be(OH)4]` (sodium beryllium hydroxide) is formed, we can analyze the two reactions mentioned in the question.

### Step-by-Step Solution:

1. **Identify the Components**:
- We need to form `Na2[Be(OH)4]`. This compound consists of sodium (Na), beryllium (Be), and hydroxide (OH) ions.

2. **First Reaction**:
- The first reaction proposed is between beryllium oxide (BeO) and sodium hydroxide (NaOH) solution.
- The reaction can be written as:
\[ \text{BeO} + 2 \text{NaOH} + 2 \text{H2O} \rightarrow \text{Na2[Be(OH)4]} \]
- In this reaction, beryllium oxide reacts with sodium hydroxide and water to form sodium beryllium hydroxide.

3. **Second Reaction**:
- The second reaction involves beryllium metal (Be) reacting with sodium hydroxide (NaOH) solution.
- The reaction can be written as:
\[ \text{Be} + 2 \text{NaOH} + 2 \text{H2O} \rightarrow \text{Na2[Be(OH)4]} + \text{H2} \]
- Here, beryllium metal reacts with sodium hydroxide and water to produce sodium beryllium hydroxide and hydrogen gas.

4. **Conclusion**:
- Both reactions lead to the formation of `Na2[Be(OH)4]`. Therefore, the correct answer to the question is that sodium beryllium hydroxide can be formed from both reactions.

5. **Final Answer**:
- The correct option is "both correct".