Oils are purified by:

Options

A. Fractional distillation
B. Steam distillation
C. vacuum distilation
D. Simple distillation.

Answer

To determine how oils are purified, we need to evaluate the different distillation methods provided in the question. Here's a step-by-step solution:

### Step 1: Understand the Distillation Methods
We are given four types of distillation methods: fractional distillation, steam distillation, vacuum distillation, and simple distillation. We need to analyze each method to see which one is suitable for purifying oils.

### Step 2: Analyze Fractional Distillation
- **Fractional Distillation**: This method is used to separate mixtures of liquids that have different boiling points, particularly miscible liquids. Since oils are not typically miscible with water and are not separated based on boiling points in this context, fractional distillation is not the correct method for purifying oils.

### Step 3: Analyze Steam Distillation
- **Steam Distillation**: This method is particularly useful for purifying heat-sensitive substances, such as essential oils. In steam distillation, steam is introduced into the distillation apparatus, which helps to carry the volatile components of the oil without decomposing them. This makes steam distillation a suitable method for purifying oils.

### Step 4: Analyze Vacuum Distillation
- **Vacuum Distillation**: This method is performed under reduced pressure and is typically used for substances that decompose at high temperatures. While it can be used for some oils, it is not the primary method for purifying oils in general.

### Step 5: Analyze Simple Distillation
- **Simple Distillation**: This method is used when there is a significant difference in boiling points between the components of a mixture. While it can be used for some oils, it is not the most effective method for purifying oils that may contain heat-sensitive components.

### Conclusion
After analyzing all the methods, the most suitable method for purifying oils is **steam distillation**.

### Final Answer
Oils are purified by **steam distillation**.

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