Select all intermolecular forces that contribute to creating a solution of salicylic acid .
A. Ion-dipole
B. London Dispersion
C. Dipole-dipole
D. H-bonding
The correct answer and explanation is :
The correct intermolecular forces that contribute to the formation of a solution of salicylic acid are:
A. Ion-dipole
B. London Dispersion
C. Dipole-dipole
D. H-bonding
Explanation:
Salicylic acid is an organic compound that has a hydroxyl group (-OH) and a carboxyl group (-COOH) as part of its structure. These functional groups, along with the aromatic benzene ring, influence the intermolecular forces that contribute to the formation of a solution of salicylic acid, depending on the solvent used.
1. Ion-dipole forces (A)
- If salicylic acid dissolves in a polar solvent, such as water, it can ionize (especially at higher temperatures or in basic conditions). The carboxyl group (-COOH) can lose a proton (H⁺) and form a carboxylate ion (RCOO⁻). The resulting ion-dipole interaction occurs between the carboxylate ion and the polar solvent molecules, such as water molecules. This interaction is significant in solutions where salicylic acid is partially or fully ionized.
2. London Dispersion Forces (B)
- These forces arise from the temporary fluctuations in electron density within molecules, leading to transient dipoles. In salicylic acid, the benzene ring, which is a nonpolar structure, exhibits London dispersion forces. These forces are weaker compared to other intermolecular forces but are still present, especially in nonpolar solvents or in the absence of strong dipole interactions.
3. Dipole-dipole interactions (C)
- Salicylic acid contains polar functional groups, particularly the hydroxyl (-OH) and carboxyl (-COOH) groups, which have permanent dipoles. In polar solvents, dipole-dipole interactions occur between the dipoles in salicylic acid and the dipoles of solvent molecules. For example, in water, the dipoles of water molecules interact with the dipoles in the -OH and -COOH groups of salicylic acid.
4. Hydrogen bonding (D)
- Hydrogen bonding is one of the most significant forces when salicylic acid dissolves in water or other polar solvents. The hydroxyl group (-OH) and carboxyl group (-COOH) in salicylic acid can form hydrogen bonds with water molecules or other potential hydrogen bond donors and acceptors in the solvent. In water, the hydrogen bonding between the -OH and -COOH groups of salicylic acid with water molecules is crucial in its solubility.
In conclusion, all the listed intermolecular forces play a role in the dissolution of salicylic acid, especially in polar solvents like water. Each type of force contributes to the overall process of solution formation by interacting with the solute (salicylic acid) and the solvent.