What are proper techniques to induce crystallization from a saturated solution?
(Select all correct answers.)
Allowing the solution to cool down.
Scratching the outside of the container with a glass rod.
Seeding the solution.
Adding a solvent that lowers the solubility of the target compound.
By adding a boiling chip to the saturated solution.
I've been told that both scratching the outside and seeding can cause crystallization, but don't take my word. I'm not totally sure.
The proper techniques to induce crystallization from a saturated solution are:
1. Allowing the solution to cool down: When a saturated solution is cooled, it reduces the solubility of the compound, increasing the chances of crystallization.
2. Scratching the outside of the container with a glass rod: Scratching the inside of the container provides a surface for the crystals to initiate and grow. This technique promotes nucleation and encourages crystallization.
3. Seeding the solution: Seeding involves adding a small crystal of the desired compound to the saturated solution. This seed crystal acts as a starting point for crystal growth, helping to induce crystallization throughout the solution.
4. Adding a solvent that lowers the solubility of the target compound: By adding a solvent (usually another liquid) that lowers the solubility of the compound, the saturated solution becomes supersaturated, promoting crystal formation.
The technique that is not correct for inducing crystallization from a saturated solution is:
- Adding a boiling chip to the saturated solution: Adding a boiling chip does not directly induce crystallization. Its purpose is to promote even boiling and prevent superheating during the heating process, which is not directly related to crystallization.