Which property of the filter prevents the collection of salt during the filtration of a saltwater solution?

• A. The pore size of the filter is larger than the salt ions, allowing them to pass through.
• B. The filter is opaque and blocks light from passing through.
• C. The filter is hydrophobic and repels water and salt.
• D. The filter is chemically reactive with salt, dissolving it.

Answer: (A)

Verified step by step guidance

1. Understand the nature of the saltwater solution: it is a homogeneous mixture where salt ions (such as Na\^+ and Cl\^-) are dissolved at the ionic level in water, forming a true solution.
2. Recognize that filtration works by physically separating particles based on size, where the filter's pores allow smaller particles or molecules to pass through while trapping larger particles.
3. Identify that salt ions are extremely small, much smaller than the pores of a typical filter paper, so they can pass through the filter along with the water.
4. Conclude that the key property preventing salt collection on the filter is the pore size being larger than the salt ions, allowing the salt to remain dissolved and pass through the filter.
5. Note that other properties like opacity, hydrophobicity, or chemical reactivity of the filter do not affect the physical separation of dissolved salt ions during filtration.