The soap molecule has a

Options

A. hydrophilic head and a hydrophobic tail
B. hydrophobic head and a hydrophilic tail
C. hydrophobic head and a hydrophobic tail
D. hydrophilic head and a hydrophilic tail

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure of Soap:**
- Soap molecules are amphiphilic, meaning they have both hydrophobic (water-repelling) and hydrophilic (water-attracting) parts.

2. **Identifying the Hydrophobic Part:**
- The hydrophobic part of the soap molecule is a long hydrocarbon chain. This part does not interact well with water and is often referred to as the "tail" of the soap molecule.

3. **Identifying the Hydrophilic Part:**
- The hydrophilic part of the soap molecule is an ionic group, typically represented as COO- (carboxylate ion) and Na+ (sodium ion). This part is attracted to water and is referred to as the "head" of the soap molecule.

4. **Combining the Two Parts:**
- The soap molecule can be visualized as having a long hydrocarbon chain (the hydrophobic tail) attached to a short ionic group (the hydrophilic head). This structure allows soap to interact with both water and oils or grease.

5. **Conclusion:**
- Therefore, a soap molecule consists of a hydrophobic tail (long hydrocarbon chain) and a hydrophilic head (ionic part, COO-Na+). This unique structure allows soap to effectively clean by surrounding grease and dirt, allowing them to be washed away with water.