One of the steps used in the process of formation of common salt from sea-water is

Question

Accepted Answer

The process of forming common salt from sea-water involves several steps, one of which is vaporisation. Let's explore why vaporisation is the correct step and why the other options are not applicable in this context.

1. **Vaporisation (Option 3):**  
   Vaporisation is the process of converting a liquid into vapor. In the context of forming common salt from sea-water, vaporisation is a crucial step. When sea-water is exposed to heat, the water component evaporates, leaving behind the dissolved salts, primarily sodium chloride (common salt). This process is typically carried out in large, shallow ponds where the sun's heat facilitates the evaporation of water. As the water vaporises, the concentration of salt increases until it crystallizes and can be collected. This method is efficient and widely used in salt production.

2. **Distillation (Option 1):**  
   Distillation involves heating a liquid to create vapor and then cooling the vapor to create a liquid. While distillation can be used to purify water by removing salts, it is not typically used in the commercial production of salt from sea-water. The goal in salt production is to remove water and leave the salt behind, not to collect purified water, which is the primary aim of distillation.

3. **Condensation (Option 2):**  
   Condensation is the process by which vapor turns back into liquid. In the context of salt production, condensation is not directly involved in the formation of salt. Instead, it is part of the water cycle where evaporated water vapor cools and returns to liquid form, often as precipitation. In salt production, the focus is on removing water, not condensing it.

4. **Filtration (Option 4):**  
   Filtration is a method used to separate solids from liquids or gases using a filter medium. While filtration can be used to remove impurities from sea-water, it is not effective for separating dissolved salts from water. The dissolved salts pass through the filter along with the water, so filtration is not a step in the formation of salt from sea-water.

In summary, vaporisation is the correct step in the process of forming common salt from sea-water because it effectively removes the water, leaving behind the salt. The other options do not achieve this goal in the context of salt production.