Which one is the most soluble in water ?

Options

A. Uric acid
B. Urea
C. Fatty acids
D. Casein

Answer

To determine which substance is the most soluble in water among the given options (uric acid, urea, fatty acid, and casein), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Options**: The options provided are:
- Uric acid
- Urea
- Fatty acid
- Casein

2. **Analyze Each Option**:
- **Fatty Acid**: Fatty acids are part of the lipid family and are generally insoluble in water. Therefore, we can eliminate this option right away.
- **Uric Acid**: Uric acid is a nitrogenous waste product that is less soluble in water compared to urea. It is excreted in a semi-solid form to conserve water, making it less favorable in terms of solubility.
- **Urea**: Urea is a nitrogenous waste product that is soluble in water. It is more soluble than uric acid and is less toxic than ammonia.
- **Casein**: Casein is a protein found in milk. Proteins generally have limited solubility in water compared to smaller molecules like urea.

3. **Compare the Remaining Options**: After eliminating fatty acid, we compare urea, uric acid, and casein:
- Urea is known to be highly soluble in water.
- Uric acid is less soluble than urea.
- Casein, being a protein, is also less soluble than urea.

4. **Conclusion**: Based on the analysis, urea is the most soluble substance in water among the options provided.

### Final Answer:
**Urea is the most soluble in water.**

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