Final answer:
The correct method for obtaining water from a salt solution is distillation, which uses heating to evaporate water and then condenses the vapor into pure liquid water, leaving salt behind.
Step-by-step explanation:
The processes that can be used to obtain water from a salt solution include filtration, decantation, evaporation, and distillation. However, the most effective method for separating water from a salt solution is distillation. Distillation takes advantage of the fact that the substances in a mixture have different boiling points. When a salt solution is heated in a distilling flask, the water, which is more volatile, boils and turns into vapor while the salt remains. This vapor is then condensed into liquid water in a condenser and collected in a separate flask, effectively separating the two substances.
The desalination process can also be achieved through methods like reverse osmosis, which uses a semipermeable membrane to filter out salt from seawater. However, for the original question provided by the student, distillation is the correct answer since it involves heating to induce phase changes—evaporation and subsequent condensation—allowing for the collection of pure water.