solvent
For each solute, identify the better solvent: water or carbon tetrachloride.
The correct answer and explanation is:
When deciding whether water or carbon tetrachloride (CCl4CCl_4) is a better solvent for a given solute, the key factors are the polarity of the solute and the principle of “like dissolves like.” Below is the detailed explanation for each solvent:
Water
Water is a highly polar solvent due to its significant dipole moment and hydrogen-bonding capability. It is particularly effective at dissolving:
- Ionic compounds: These dissociate into ions, which interact strongly with the partial charges in water molecules.
- Polar covalent molecules: Compounds with permanent dipoles (e.g., alcohols, sugars, and acids) readily form hydrogen bonds or dipole-dipole interactions with water.
Examples of solutes better dissolved in water:
- Sodium chloride (NaCl): An ionic compound that dissociates into Na+Na^+ and Cl−Cl^-, which are stabilized by water molecules.
- Ethanol (C2H5OHC_2H_5OH): Its hydroxyl group interacts with water through hydrogen bonding.
- Glucose (C6H12O6C_6H_{12}O_6): Highly polar and forms hydrogen bonds with water.
Carbon Tetrachloride (CCl4CCl_4)
Carbon tetrachloride is a nonpolar solvent due to its symmetric tetrahedral structure and the absence of a net dipole moment. It is effective for dissolving:
- Nonpolar molecules: These include hydrocarbons and other substances without significant polarity or hydrogen-bonding capability.
- Lipophilic compounds: Compounds that are soluble in nonpolar environments.
Examples of solutes better dissolved in CCl4CCl_4:
- Iodine (I2I_2): A nonpolar molecule that dissolves well in CCl4CCl_4 through London dispersion forces.
- Hexane (C6H14C_6H_{14}): A hydrocarbon that is miscible with CCl4CCl_4 due to similar nonpolar characteristics.
- Chloroform (CHCl3CHCl_3): While slightly polar, it is more soluble in CCl4CCl_4 due to weak intermolecular interactions.
Conclusion
Water is better for ionic and polar compounds due to its high polarity and hydrogen-bonding ability, whereas CCl4CCl_4 excels at dissolving nonpolar substances due to its symmetry and lack of polarity.