KRF2, or potassium fluoride, is an ionic compound. In this compound, potassium (K) donates one electron to become a positively charged ion (K+), while fluorine (F) accepts that electron to become a negatively charged ion (F–). The strong electrostatic attraction between these oppositely charged ions results in the formation of an ionic bond, characteristic of ionic compounds.
When it comes to solubility, the nature of the solvent plays a crucial role in dissolving ionic compounds like KRF2. Water, being a polar solvent, is particularly effective at dissolving ionic substances. This is due to the polarity of water molecules, which have a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. The positive end of the water molecules can attract and surround the negative fluoride ions, while the negative end can do the same with the positive potassium ions, effectively pulling them apart into solution.
In contrast, carbon tetrachloride (CCl4) is a nonpolar solvent. It lacks the polarity necessary for effectively interacting with and dissolving ionic compounds. Nonpolar solvents generally do not dissolve ionic substances well because there is no attraction between the solvent molecules and the charged ions of the ionic compound.
Therefore, for dissolving KRF2, water is the superior choice over carbon tetrachloride due to its ability to effectively solvate ionic species.