Final answer:
Filtering cannot separate water from salt in a saltwater mixture because the salt is dissolved at the molecular level, forming a homogeneous solution which cannot be separated by filtration which is effective for heterogeneous mixtures.
Step-by-step explanation:
To answer the question on why it would not work to filter a saltwater mixture to separate the water from the salt, the correct choice is (d) The mixture is a solution, and filtering is ineffective for separating dissolved substances. Filtration typically separates solid particles from liquids by using a filter with pores that are large enough to let the liquid through while trapping the solids. However, in the case of a solution like saltwater, the salt (solute) is completely dissolved in the water (solvent) and its particles are uniformly distributed at the molecular level, making it impractical to separate them using conventional filtration methods.
A more effective method for separating salt from water would be a process called distillation, which takes advantage of the different boiling points of salt and water to evaporate and then condense the water, leaving the salt behind.
The reason why filtering would not work to separate water from salt in a saltwater mixture is because the mixture is a solution, and filtering is ineffective for separating dissolved substances. When salt is dissolved in water, the salt particles become very small and uniformly distributed throughout the water, making it difficult to separate them using a filter. Filtration is typically used to separate a heterogeneous mixture of liquid and solid, where the solid particles can be trapped by the filter while the liquid passes through.