Water is a polar solvent and carbon tetrachloride (CCl4) is a nonpolar solvent. In which solvent is each of the following more likely to be soluble?
Solute
Polar or Nonpolar
H2O or CCl4
O2 (g)
C6H12O6 (s) (glucose)
CO2 (g)
KCl (s)
The Correct Answer and Explanation is:
Solubility Table
| Solute | Polar or Nonpolar | More Soluble In |
|---|---|---|
| O₂ (g) | Nonpolar | CCl₄ (nonpolar) |
| C₆H₁₂O₆ (s) | Polar | H₂O (polar) |
| CO₂ (g) | Nonpolar (slightly polar) | CCl₄ (nonpolar) |
| KCl (s) | Ionic (highly polar) | H₂O (polar) |
Explanation
Solubility depends on the principle “like dissolves like”, which means polar solutes dissolve best in polar solvents, and nonpolar solutes dissolve best in nonpolar solvents.
Water (H₂O) is a polar solvent due to its bent molecular geometry and strong hydrogen bonding. This makes it highly effective at dissolving polar and ionic compounds by stabilizing separated ions or polar molecules. Carbon tetrachloride (CCl₄) is a nonpolar solvent due to its symmetrical tetrahedral geometry and equal distribution of charge, making it better for dissolving nonpolar substances.
O₂ (g) is a nonpolar molecule composed of two identical oxygen atoms sharing electrons equally. Since it lacks polarity, it does not interact well with polar solvents like water. Instead, O₂ dissolves better in nonpolar solvents such as CCl₄ through London dispersion forces.
Glucose (C₆H₁₂O₆) is a polar molecule due to its many hydroxyl (–OH) groups, which can form hydrogen bonds with water. These interactions allow glucose to dissolve readily in water. In contrast, it would not be soluble in CCl₄, as nonpolar solvents cannot form such interactions.
CO₂ (g) is a linear molecule with slight polarity in each bond, but the molecule as a whole is nonpolar due to its symmetry. It dissolves better in nonpolar solvents like CCl₄ through dispersion forces, although it has limited solubility in water where it can slowly form carbonic acid (H₂CO₃).
KCl (s) is an ionic compound made of K⁺ and Cl⁻ ions. These ions are highly charged and polar. Water, a polar solvent, dissolves KCl effectively by surrounding and stabilizing the separated ions. CCl₄ cannot do this, making it a poor solvent for ionic compounds.
Thus, the polarity of both the solute and solvent determines solubility.
