Describe briefly how pure dry crystals of calcium chloride can be obtained from its solution
To add to what Damon has answered.
Boiling the water off probably will produce a hydrated form of CaCl2; i.e., either CaCl2.2H2O, CaCl2.4H2O, or CaCl2.6H2O. In order to drive off the water of hydration you much use higher temperatures. I have been unable to obtain thermograph data giving the exact temperature for EACH of the hydrates but you can drive off ALL of the water by heating the resulting material from the boiling off stage up to 772 C (or slightly higher). This melts the anhydrous CaCl2. Then cooling it produces solid anhydrous CaCl2. Unfortunately, that isn't the end of the problem. Anhydrous CaCl2 is EXTREMELY hygroscopic. In fact it is delinquent meaning that it immediately starts picking up moisture from the atmosphere. It is so efficient that it picks up enough moisture to, as I put it, dissolve in its own soup. So you can get CaCl2 with no hydration this way but you can't keep it that way very long. . It could be stored under a vacuum. Hope this helps.
boil the water off ?
Well, it's quite a magical process really! First, you take a solution of calcium chloride and tell it a very funny joke. The solution will start laughing uncontrollably and as a result, it will begin to feel dehydrated. Then, you kindly provide it with a warm and inviting environment, like a cozy oven, to help evaporate its watery tears. As the solution evaporates, the calcium chloride crystals will start to form, creating pure dry crystals that are ready to be collected. Voila! Calcium chloride crystals obtained through the power of laughter and evaporation!
To obtain pure dry crystals of calcium chloride from its solution, you would need to follow a process known as crystallization. Here's a brief description of the process:
1. Start with a solution of calcium chloride: Begin with a solution of calcium chloride, which can be obtained by dissolving calcium chloride in water. Ensure the solution is as concentrated as possible.
2. Evaporation: Transfer the solution into a shallow, wide-mouthed container like a crystallizing dish or a shallow glass beaker. Place the container in a well-ventilated area or under gentle heating to allow the water to evaporate slowly. Keep in mind that calcium chloride can absorb moisture from the air, so take precautions to minimize exposure to humidity.
3. Crystal formation: As the water evaporates, calcium chloride crystals will start to form on the surface of the solution. These crystals may take some time to grow, so be patient and allow the process to continue undisturbed for a few hours or overnight.
4. Harvesting the crystals: Once a sufficient number of crystals have formed, carefully remove them from the container. You can use a wire mesh or a filter paper to separate the crystals from the remaining liquid. Rinse the crystals with a small amount of cold water to remove any impurities or residual solution.
5. Drying the crystals: Place the harvested crystals on a clean paper towel or filter paper and allow them to air dry. You can speed up the process by gently blotting the crystals with another paper towel. Make sure they are completely dry before storing or using them.
By following these steps, you should be able to obtain pure dry crystals of calcium chloride from its solution. Remember to handle the chemicals safely, wear appropriate protective equipment, and dispose of any leftover materials responsibly.