Separation of two substances by crystallisation depends upon their differences in

Options

A. densities
B. solubility
C. melting points
D. boiling points

Answer

**Step-by-Step Solution:**

1. **Understanding Crystallization**: Crystallization is a separation technique used to purify solid compounds. It involves the formation of solid crystals from a solution.

2. **Identifying the Components**: In this scenario, we have two substances (impurities) mixed in a solution. The goal is to separate these two substances.

3. **Role of Solubility**: The key factor that allows for the separation of these two substances is their difference in solubility. Solubility refers to the ability of a substance to dissolve in a solvent.

4. **Less Soluble Substance**: The substance that is less soluble in the solvent will not dissolve as readily and will tend to form solid crystals when the solution is cooled or evaporated.

5. **More Soluble Substance**: Conversely, the substance that is more soluble will remain dissolved in the solution and will not crystallize out.

6. **Separation Process**: By allowing the less soluble substance to crystallize out of the solution, we can then filter the mixture to separate the solid crystals from the liquid solution.

7. **Conclusion**: Therefore, the separation of two substances by crystallization depends upon their differences in solubility.

**Final Answer**: The separation of two substances by crystallization depends upon their differences in **solubility**.

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