Which method would best separate a mixture of sand and salt?

• A. Filter the dry mixture to separate the sand from the salt.
• B. Add water to dissolve the salt, filter to remove the sand, then evaporate the water to recover the salt.
• C. Heat the mixture directly to evaporate the sand and leave the salt behind.
• D. Use a magnet to attract the salt away from the sand.

Answer: (B)

Verified step by step guidance

1. Recognize that sand is insoluble in water, while salt (sodium chloride) is soluble in water. This difference in solubility is key to separating the two substances.
2. Add water to the mixture to dissolve the salt, creating a saltwater solution, while the sand remains undissolved as a solid.
3. Use filtration to separate the solid sand from the saltwater solution. The sand will stay on the filter paper, and the saltwater will pass through as the filtrate.
4. Evaporate the water from the saltwater solution by heating it gently. This will leave behind the solid salt crystals after the water has completely evaporated.
5. Understand why the other methods are ineffective: filtering the dry mixture won't separate salt since it is dissolved only in water; heating directly won't evaporate sand because it has a very high melting point; and using a magnet won't work because neither sand nor salt is magnetic.