Introduction:
When a mixture of solid and liquid is present, we need to separate the solid from the liquid. The separation process depends on the properties of the mixture components.

Filtration:
Filtration is a process of separating solid particles from a liquid using a filter. The solid particles are trapped in the filter, and the liquid passes through it. Filtration is used when the solid particles are larger in size than the liquid molecules.

Evaporation:
Evaporation is a process of converting a liquid into a gas by heating it. When a mixture of solid and liquid is heated, the liquid evaporates, leaving behind the solid particles. Evaporation is used when the solid particles are soluble in the liquid.

Obtaining a soluble solid:
To obtain a soluble solid from a mixture of solid and liquid, we need to use evaporation. When the solution is heated, the liquid evaporates, leaving behind the solid particles. If the solid particles are soluble in the liquid, they will dissolve in the liquid and form a solution.

Conclusion:
Filtration is used to separate solid particles that are larger in size than the liquid molecules, while evaporation is used to separate a soluble solid from a liquid. To obtain a soluble solid from a mixture of solid and liquid, we need to use evaporation.

Evaporation because filtration is done for insoluble solid