Which of the following steps is not involved in the preparation of sodium chloride from sea water?

Options

A. evaporation
B. dissolution in water
C. recryztalllisation
D. distillation

Answer

To determine which step is not involved in the preparation of sodium chloride (table salt) from seawater, let's break down the process into clear steps:

### Step-by-Step Solution:

1. **Collection of Seawater**: The first step in the preparation of sodium chloride from seawater is to collect seawater. Seawater contains dissolved salts, including sodium chloride.

2. **Evaporation**: After collecting the seawater, the next step is to evaporate the water. This is done by heating the seawater, which causes the water to evaporate and leaves behind the dissolved salts, including sodium chloride.

3. **Formation of Crystals**: As the water evaporates, sodium chloride crystals begin to form. This is a result of the saturation of the solution as the water content decreases.

4. **Re-crystallization**: The formed sodium chloride crystals may not be pure. To purify them, a process called re-crystallization is performed. This involves dissolving the crystals in a small amount of water and then evaporating the water again to obtain purer sodium chloride crystals.

5. **Distillation**: This step is not involved in the preparation of sodium chloride from seawater. Distillation is a process used to separate components of a mixture based on different boiling points, which is not necessary for obtaining sodium chloride from seawater.

### Conclusion:
The step that is not involved in the preparation of sodium chloride from seawater is **distillation**.

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