What is the principle involved in the following methods of separation of mixtures ?
(i) Fractional crystallization
(ii) Magnetic separation
(iii) Gravity method
(iv) Separating funnel method
(v) Distillation
(vi) Fractional distillation
(vii) Preferential liquifaction
(viii) Chromatography
(ix) Fractional evaporation

Explanation

To answer the question regarding the principles involved in various methods of separation of mixtures, we can break down each method as follows:

### Step-by-Step Solution:

1. **Fractional Crystallization**
- **Principle**: The principle of fractional crystallization is based on the **solubility of solids** in a given solvent. Different solids have different solubility levels, which allows them to crystallize at different rates.

2. **Magnetic Separation**
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