Emulsions are also called the colloidal solutions in which the disperse phase as well as dispersion medium are liquids. It may be oil-in-water or water-inoil type Emulsifiers can be sued to stabilize the emulsion. Soaps, detergents, proteins, and gums are used as emulsifiers.
Which of the following examples is/are oil-in-water-type emulsion?

Options

A. Ink
B. Detergent
C. Soap
D. Milk

Answer

To determine which of the given examples are oil-in-water type emulsions, we need to analyze each option based on the definition of emulsions. An oil-in-water emulsion consists of oil droplets dispersed in water.

### Step-by-Step Solution:

1. **Understand the Definition of Emulsions**:
- Emulsions are colloidal solutions where both the dispersed phase and the dispersion medium are liquids.
- In oil-in-water emulsions, the dispersed phase is oil, and the dispersion medium is water.

2. **Analyze Each Option**:
- **Option 1: Ink**: Ink is primarily a water-based solution with pigments or dyes. It is not an oil-in-water emulsion.
- **Option 2: Detergent**: Detergents are surfactants that can help in emulsifying oils in water, but they are not themselves classified as emulsions. They can stabilize emulsions but are not oil-in-water emulsions.
- **Option 3: Soap**: Soaps can act as emulsifiers and help stabilize oil-in-water emulsions, but they are not emulsions themselves.
- **Option 4: Milk**: Milk is a classic example of an oil-in-water emulsion, where fat (oil) is dispersed in water, making it the correct answer.

3. **Conclusion**:
- The only option that qualifies as an oil-in-water emulsion is **Option 4: Milk**.

### Final Answer:
The correct option is **Option 4: Milk**.

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