When soap solution dissolves in water , then the surface tension of soap solution is

Options

A. reduced
B. increased
C. remains constant
D. zero

Answer

To solve the question regarding the effect of soap solution on the surface tension of water, we can break it down into a few logical steps:

### Step-by-Step Solution:

1. **Understanding Surface Tension**:
- Surface tension is a property of liquids that arises due to the cohesive forces between liquid molecules. In pure water, these forces are strong, resulting in a relatively high surface tension.

2. **Effect of Soap on Water**:
- When soap is added to water, it introduces molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts. This structure is crucial in understanding how soap affects surface tension.

3. **Intermolecular Forces**:
- The soap molecules disrupt the cohesive forces between water molecules. The hydrophobic tails of soap molecules push against the water molecules, which reduces the overall intermolecular attraction among water molecules.

4. **Decrease in Surface Tension**:
- As the intermolecular forces between water molecules are weakened due to the presence of soap, the surface tension of the soap solution decreases. This is because the cohesive forces that contribute to surface tension are diminished.

5. **Conclusion**:
- Therefore, when soap solution dissolves in water, the surface tension of the soap solution decreases.

### Final Answer:
The surface tension of the soap solution decreases when it dissolves in water.

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