Identify a Hydroxide which is Highly Soluble in Water.

One hydroxide that is highly soluble in water is sodium hydroxide (NaOH), commonly known as caustic soda or lye. Here's a detailed explanation:

### 1. **Chemical Structure**
- Sodium hydroxide consists of sodium (Na⁺) ions and hydroxide (OH⁻) ions. The ionic nature of NaOH allows it to dissolve easily in water.

### 2. **Solubility**
- Sodium hydroxide is highly soluble in water, with a solubility of about 111 g per 100 mL at 20°C. When dissolved in water, it dissociates completely into its constituent ions:
\[
\text{NaOH (s)} \rightarrow \text{Na}^+ (aq) + \text{OH}^- (aq)
\]

### 3. **Properties of the Solution**
- The solution of sodium hydroxide in water is strongly alkaline (basic) due to the presence of hydroxide ions. This high concentration of hydroxide ions makes the solution highly caustic and can lead to chemical burns.

### 4. **Applications**
- Due to its high solubility and strong basicity, sodium hydroxide is widely used in various applications, including:
- Manufacturing soap and detergents.
- Water treatment processes to adjust pH.
- Food processing as a pH regulator.
- Chemical synthesis and industrial processes.

### Conclusion
Sodium hydroxide is a prime example of a hydroxide that is highly soluble in water, making it an essential chemical in both industrial and laboratory settings.