Indicate the principal type of solute–solvent interaction in each of the following solutions and rank the solutions from weakest to strongest solute–solvent interaction: (c) methanol (CH₃OH) in water

Verified step by step guidance

1. Identify the types of molecules involved in the solution: Methanol (CH₃OH) and water (H₂O) are both polar molecules.
2. Recognize the type of intermolecular forces present: Both methanol and water can form hydrogen bonds, which are a type of strong dipole-dipole interaction.
3. Determine the principal type of solute-solvent interaction: Since both solute (methanol) and solvent (water) can form hydrogen bonds, the principal interaction in this solution is hydrogen bonding.
4. Compare the strength of the hydrogen bonds in the solution: Methanol and water both have similar abilities to form hydrogen bonds, suggesting a strong solute-solvent interaction.
5. Rank the solution in terms of solute-solvent interaction strength: If comparing with other solutions, consider the ability of other solutes to form hydrogen bonds or other interactions with their solvents. Methanol in water would likely rank high due to the strong hydrogen bonding.

Key Concepts

Solute-Solvent Interactions

Solute-solvent interactions refer to the forces that occur between solute particles and solvent molecules when a solution is formed. These interactions can include hydrogen bonding, dipole-dipole interactions, and London dispersion forces. The strength and type of these interactions significantly influence the solubility and properties of the solution.

Hydrogen Bonding

Hydrogen bonding is a specific type of strong dipole-dipole interaction that occurs when hydrogen is covalently bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine. In the case of methanol in water, both methanol and water can form hydrogen bonds, leading to strong solute-solvent interactions that enhance solubility and affect the physical properties of the solution.

Ranking Interactions

Ranking solute-solvent interactions involves comparing the strength of different types of interactions present in various solutions. This ranking is typically based on the nature of the interactions, such as hydrogen bonding being stronger than dipole-dipole interactions. Understanding these rankings helps predict the behavior of solutions, including solubility and boiling point elevation.