Which of the following forms micelles in solutions of higher concentrations 

Options

A. Sodium carbonate
B. Sodium bicarbonate
C. Potassium acetate
D. Sodium stearate

Answer

To determine which of the given options forms micelles in solutions of higher concentrations, we need to understand the concept of micelles and the conditions under which they are formed.

### Step-by-Step Solution:

1. **Understanding Micelles**:
- Micelles are aggregates of surfactant molecules that form in solution when the concentration exceeds a certain threshold known as the critical micelle concentration (CMC).

2. **Structure of Surfactants**:
- Surfactants typically have a dual nature: a hydrophobic (water-repelling) tail and a hydrophilic (water-attracting) head. The hydrophobic tail is usually a long hydrocarbon chain, while the hydrophilic head can be ionic or polar.

3. **Identifying the Components**:
- For a substance to form micelles, it must possess both a long hydrocarbon chain (hydrophobic part) and a polar or ionic group (hydrophilic part).

4. **Analyzing Sodium Stearate**:
- Sodium stearate, which is the salt of stearic acid, has the formula C15H31COONa.
- Here, C15H31 is the long hydrocarbon chain (hydrophobic part), and the COONa part is the polar group (hydrophilic part).

5. **Conclusion**:
- Since sodium stearate has both a hydrophobic tail and a hydrophilic head, it can form micelles when the concentration exceeds the CMC. Therefore, it is the correct choice among the options provided.

### Final Answer:
- The substance that forms micelles in solutions of higher concentrations is **Sodium Stearate**.