Final answer:
A solvent is added to the test tube with the solid being crystalized to promote the dissolution of the solid into its individual ions, atoms, or molecules.
Step-by-step explanation:
Along with the solid being crystalized, a solvent is generally added to the test tube in the dissolution step. The solvent, such as water, ethanol, or another appropriate liquid, is crucial because it disrupts the crystal lattice forces holding the solid together, allowing the individual ions, atoms, or molecules of the solute to become evenly dispersed throughout the solvent. The rate of dissolution can be affected by factors like temperature, stirring, and the presence of other substances that can affect the solubility of the solute.