Solid sodium chloride can be obtained from its solution by evaporation.
The Method: Evaporation
The process of obtaining solid sodium chloride (common table salt) from a sodium chloride solution is primarily achieved through evaporation. This method relies on the difference in physical properties between water and sodium chloride.
As stated in the provided information, "Solid sodium chloride can be obtained from its solution by evaporation."
The Evaporation Process
When a sodium chloride solution is allowed to evaporate, the following happens:
- The solution is typically placed in an open container or spread out to maximize the surface area exposed to air.
- Heat energy (from the sun, a heater, or even just the surrounding air) is absorbed by the water molecules in the solution.
- This energy causes the water molecules to change from a liquid state into a gaseous state, known as water vapour.
- According to the reference, "By this, water present in the solution evaporated in the form of water vapour to the surroundings".
- As the water vapour leaves the container and disperses into the environment, the solute that was dissolved in the water – the solid sodium chloride – remains behind.
- The reference confirms this by stating, "and solid sodium chloride is left behind in the container."
Essentially, the water evaporates, leaving the solid salt crystals.
Summary of Transformation
The process can be simply visualized as:
| Before Evaporation | After Evaporation |
|---|---|
| Sodium Chloride Solution | Solid Sodium Chloride |
| Water (Liquid) | Water Vapour (Gas) |
| Sodium Chloride (Dissolved) | Sodium Chloride (Solid) |
This straightforward technique is widely used, from natural salt flats where sunlight and wind drive evaporation to controlled industrial processes.
