What is the correct sequence to obtain a pure dry salt from a soluble salt?

What is the correct sequence to obtain a pure dry salt from a soluble salt?

• A. Filter the solution, crystallize, and dry the solid.
• B. React the acid with a base (neutralization) to form a soluble salt; filter, crystallize, and dry to obtain the dry salt.
• C. Evaporate the solvent to dryness.
• D. Precipitate a salt by adding another salt.

Answer: (B)

Forming the salt in solution and then purifying it by crystallization and drying gives the pure solid efficiently. First, neutralization creates the salt in aqueous solution with the correct ions and removes excess reagents, so you have the right chemical species present. Then filtering removes any undissolved material. Next, crystallizing lets the dissolved salt come out as crystals, leaving most impurities behind in solution. Finally, drying removes all water from the crystals to give a pure, dry salt. Evaporating the solvent to dryness can leave behind impurities or hydrates and doesn’t guarantee impurity removal. Precipitating by adding another salt can produce a different compound or a mixture. Filtering first alone doesn’t ensure the salt crystallizes cleanly, and skipping the formation step means the exact salt you want may not be present in the solution.

Forming the salt in solution and then purifying it by crystallization and drying gives the pure solid efficiently. First, neutralization creates the salt in aqueous solution with the correct ions and removes excess reagents, so you have the right chemical species present. Then filtering removes any undissolved material. Next, crystallizing lets the dissolved salt come out as crystals, leaving most impurities behind in solution. Finally, drying removes all water from the crystals to give a pure, dry salt.

Evaporating the solvent to dryness can leave behind impurities or hydrates and doesn’t guarantee impurity removal. Precipitating by adding another salt can produce a different compound or a mixture. Filtering first alone doesn’t ensure the salt crystallizes cleanly, and skipping the formation step means the exact salt you want may not be present in the solution.