which of the following statement is not true about the oil - in - water type emulsion ?

Options

A. Addition of small amount of water , no separate layer of water is formed
B. Addition of a small amount of oil soluble dye renders the entire emulsion coloured
C. Addition of oil results in the formation of two layers
D. Addition of a small amount of an electroyte increases the conductivity of the emulsion

Answer

To determine which statement is not true about oil-in-water type emulsions, we need to analyze each statement provided.

### Step-by-Step Solution:

1. **Understanding Oil-in-Water Emulsion**:
- An oil-in-water emulsion consists of tiny droplets of oil dispersed in a continuous water phase. This means that water is the main medium, while oil is the dispersed phase.

2. **Evaluating the Statements**:
- **Statement 1**: "Addition of a small amount of water, no separate layer of water is formed."
- **Analysis**: True. Since water is the continuous phase, adding more water will not create a separate layer; it will simply increase the amount of the continuous phase.

- **Statement 2**: "The addition of a small amount of oil-soluble dye renders the entire emulsion colored."
- **Analysis**: Not true. If we add an oil-soluble dye, it will not color the entire emulsion because the dye will only dissolve in the oil phase, which is in a much smaller quantity compared to the water phase. Therefore, the emulsion will not change color significantly.

- **Statement 3**: "The addition of oil results in the formation of two layers."
- **Analysis**: True. If more oil is added, it will not dissolve completely in the water and will form a separate layer on top of the water due to the immiscibility of oil and water.

- **Statement 4**: "The addition of a small amount of an electrolyte increases the conductivity of the solution."
- **Analysis**: True. Electrolytes dissociate into ions in water, which increases the conductivity of the solution.

3. **Conclusion**:
- The statement that is not true about oil-in-water emulsions is **Statement 2**: "The addition of a small amount of oil-soluble dye renders the entire emulsion colored."