what of the following is not an emulsion ?

Options

A. Butter
B. Ice cream
C. Milk
D. Cloud

Answer

To determine which of the following options is not an emulsion, we first need to understand what an emulsion is.

### Step 1: Define Emulsion
An emulsion is a colloidal system in which one liquid is dispersed in another liquid. There are two main types of emulsions:
- **Oil in Water (O/W)**: where oil droplets are dispersed in water.
- **Water in Oil (W/O)**: where water droplets are dispersed in oil.

### Step 2: Analyze the Options
Now, let's analyze the options given in the question:
1. **Butter**: This is an emulsion of water in fat (W/O).
2. **Ice Cream**: This is also an emulsion, typically oil in water (O/W).
3. **Milk**: Milk is a colloidal emulsion of fat globules in water (O/W).
4. **Cloud**: Clouds consist of tiny water droplets suspended in air, which is an aerosol, not an emulsion.

### Step 3: Identify the Correct Answer
From the analysis above, we can see that:
- Butter, Ice Cream, and Milk are all emulsions.
- Cloud is not an emulsion; it is an aerosol.

Thus, the correct answer is **Option 4: Cloud**.

### Summary of the Solution
The option that is not an emulsion is **Cloud**.