Amphoteric hydroxides react with both alkalies and acids. Which of the following Group 2 metal hydroxides is soluble in sodium hydroxide?

Options

A. `Be(OH)_(2)`
B. `Mg(OH)_(2)`
C. `Ca(OH)_(2)`
D. `Ba(OH)_(2)`

Explanation

To determine which Group 2 metal hydroxide is soluble in sodium hydroxide, we need to analyze the properties of the hydroxides of Group 2 elements (alkaline earth metals).

### Step-by-Step Solution:

1. **Understanding Amphoteric Hydroxides**:
Amphoteric hydroxides can react with both acids and bases. This means they can act as both an acid and a base depending on the reacting species.

2. **Identifying Group 2 Metal Hydroxides**:
The Group 2 metals include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). Their corresponding hydroxides are Be(OH)₂, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂, and Ba(OH)₂.

3. **Solubility in Sodium Hydroxide**:
We need to find out which of these hydroxides can dissolve in sodium hydroxide (NaOH). Among the Group 2 metal hydroxides, beryllium hydroxide (Be(OH)₂) is known to be amphoteric.

4. **Reaction of Beryllium Hydroxide with Sodium Hydroxide**:
When beryllium hydroxide reacts with sodium hydroxide, it forms sodium beryllate (Na₂BeO₂) and hydrogen gas (H₂). The reaction can be represented as:
\[ \text{Be(OH)}_2 + 2 \text{NaOH} \rightarrow \text{Na}_2\text{BeO}_2 + 2 \text{H}_2\text{O} \]
This shows that beryllium hydroxide is soluble in sodium hydroxide.

5. **Conclusion**:
Based on the above analysis, the Group 2 metal hydroxide that is soluble in sodium hydroxide is **Beryllium Hydroxide (Be(OH)₂)**.

### Final Answer:
Beryllium hydroxide (Be(OH)₂) is the Group 2 metal hydroxide that is soluble in sodium hydroxide.

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