Which molecule would you expect to be more soluble in water: CCl4 or CH2Cl2?

Verified step by step guidance

1. Identify the key property that affects solubility in water: polarity. Water is a polar solvent, so polar molecules are generally more soluble in water than nonpolar molecules.
2. Examine the molecular structure of CCl4 (carbon tetrachloride). It is a symmetrical molecule with four chlorine atoms bonded to a central carbon atom. This symmetry makes CCl4 a nonpolar molecule.
3. Examine the molecular structure of CH2Cl2 (dichloromethane). It has two hydrogen atoms and two chlorine atoms bonded to a central carbon atom. The presence of the more electronegative chlorine atoms creates a dipole moment, making CH2Cl2 a polar molecule.
4. Compare the polarity of the two molecules: CCl4 is nonpolar, while CH2Cl2 is polar. Since water is a polar solvent, it will better dissolve polar substances.
5. Conclude that CH2Cl2, being polar, is expected to be more soluble in water than CCl4, which is nonpolar.

Key Concepts

Polarity

Polarity refers to the distribution of electrical charge over the atoms in a molecule. Polar molecules have a significant difference in electronegativity between their atoms, leading to a dipole moment. This characteristic affects solubility, as polar substances tend to dissolve well in polar solvents like water, while nonpolar substances do not.

Intermolecular Forces

Intermolecular forces are the forces of attraction or repulsion between neighboring particles (atoms, molecules, or ions). In the context of solubility, stronger intermolecular forces between solute and solvent molecules enhance solubility. Water, being a polar solvent, interacts favorably with polar solutes through hydrogen bonding and dipole-dipole interactions.

Like Dissolves Like

The principle of 'like dissolves like' states that polar solvents tend to dissolve polar solutes, while nonpolar solvents dissolve nonpolar solutes. This concept is crucial for predicting solubility; since water is polar, it will more readily dissolve polar molecules, such as CH2Cl2, compared to nonpolar molecules like CCl4.