Final answer:
CaCl2 is more soluble than CCl4 because it ionizes in water, creating strong solute-solvent interactions, whereas CCl4 does not ionize and is molecular in solution.
Step-by-step explanation:
Between the substances CCl4 (carbon tetrachloride) and CaCl2 (calcium chloride), CaCl2 is more soluble because when it dissolves, it separates into three ions (one Ca2+ and two Cl− ions), compared to the molecular dissolution of CCl4, which does not ionize. Solubility often increases with the ability to form strong solute-solvent interactions. In the case of CaCl2, the ionic nature allows it to interact strongly with water, a polar solvent, making it highly soluble. This is different from the expectation that solutes with similar polarity to the solvent tend to be more soluble, such as I2 being more soluble in the nonpolar solvent CCl4 than in the polar solvent H2O, as both solute and solvent are nonpolar in that case.