1. Prepare the Solution:
- Dissolve a known mass of salt (sodium chloride) in a beaker of distilled water. Stir the mixture until the salt is completely dissolved.
- Add hydrochloric acid (HCl) slowly to the salt solution while stirring continuously. Keep adding HCl until the solution becomes slightly acidic (pH less than 7).
- Heat the solution gently to aid in the dissolution of any remaining salt.
2. Filter the Solution:
- Set up a filtration system using a Buchner funnel, filter paper, and a vacuum flask.
- Pour the heated salt and hydrochloric acid solution into the Buchner funnel. The filter paper will trap any undissolved particles, allowing the solution to pass through.
3. Evaporate the Solution:
- Collect the filtrate from the filtration process in a clean beaker.
- Place the beaker containing the filtrate on a hot plate or over a heating source.
- Heat the filtrate until most of the water evaporates, leaving behind a concentrated solution of calcium chloride and sodium chloride.
4. Crystallization:
- Allow the concentrated solution to cool slowly at room temperature. As the solution cools, calcium chloride will start to crystallize out of the solution.
- You may need to scratch the sides of the beaker to encourage crystallization.
5. Separate the Crystals:
- Once the solution has cooled completely, filter the mixture again using a Buchner funnel and filter paper. This will separate the calcium chloride crystals from the remaining liquid solution.
- Wash the crystals with a small amount of cold water to remove any residual impurities.
6. Dry the Crystals:
- Spread the calcium chloride crystals on a watch glass or a clean surface lined with filter paper.
- Place the watch glass in a warm, dry place to allow the crystals to dry thoroughly.
The dried calcium chloride crystals can now be stored in an airtight container for future use.
