Which one of the following forms micelles in aqueous solution above certain concentration?

Options

A. Urea
B. Dodecyl trimethyl ammonium chloride
C. Pyridinium chloride
D. Glucose

Explanation

To solve the question "Which one of the following forms micelles in aqueous solution above certain concentration?", we will analyze each option provided:

### Step 1: Understand Micelles and Critical Micelle Concentration (CMC)
Micelles are aggregates of surfactant molecules that form in solution when the concentration of surfactant exceeds a certain threshold known as the Critical Micelle Concentration (CMC). Below this concentration, surfactants exist primarily as individual molecules.

**Hint:** Remember that CMC is the concentration at which micelles start to form in a solution.

### Step 2: Analyze Each Option
1. **Urea**: Urea is a small organic molecule and does not have surfactant properties. It does not form micelles in aqueous solution.

**Hint:** Consider the properties of urea; it is not a surfactant.

2. **Dodecyl Trimethyl Ammonium Chloride**: This is a cationic surfactant. Surfactants like this one can form micelles in aqueous solutions when their concentration exceeds the CMC.

**Hint:** Look for surfactants that are known to form micelles.

3. **Pyridinium Chloride**: While this is an organic compound, it is not typically classified as a surfactant and does not form micelles in aqueous solutions.

**Hint:** Think about the structure and properties of pyridinium chloride; is it a surfactant?

4. **Glucose**: Glucose is a simple sugar and does not have surfactant properties. It does not form micelles in solution.

**Hint:** Consider whether glucose has the necessary structure to act as a surfactant.

### Step 3: Conclusion
After analyzing all the options, we find that the only compound that forms micelles in aqueous solution above a certain concentration is **Dodecyl Trimethyl Ammonium Chloride**. Therefore, the correct answer is:

**Answer: Dodecyl Trimethyl Ammonium Chloride (Option 2)**

### Summary of Steps:
1. Understand the concept of micelles and CMC.
2. Analyze each option for surfactant properties.
3. Conclude that only Dodecyl Trimethyl Ammonium Chloride can form micelles.