Explain the steps involved in crystallization in separation

Answer 1

Crystallization is a separation technique used to purify a solid compound by heating a solution of the compound until it reaches its saturation point and allowing it to cool, leading to the formation of crystals. The steps involved in crystallization are as follows:

1. Dissolution: The solid compound is dissolved in a hot solvent to form a saturated solution. The solvent is chosen based on its ability to dissolve the compound at high temperatures but not at lower temperatures.

2. Heating: The solution is heated to dissolve as much of the compound as possible. Heating also helps to remove any impurities that may be present in the compound.

3. Cooling: The solution is slowly cooled down, causing the solubility of the compound to decrease. As a result, the compound starts to crystallize out of the solution.

4. Crystallization: As the solution cools further, crystals of the compound form and settle at the bottom of the container. The crystals can be further purified by filtering them out of the solution.

5. Washing: The crystals are washed with a small amount of cold solvent to remove any remaining impurities or solvent trapped in the crystals.

6. Drying: The purified crystals are then dried to remove any remaining solvent. This can be done by placing the crystals on a filter paper and allowing them to air dry or by using a desiccator.

7. Collection: Once the crystals are completely dry, they can be collected and stored for future use. The purity of the crystals can be determined by performing additional tests, such as melting point analysis.