WAEC Chemistry 2018 Paper

Concept:The solubility of a gas in water depends on the weak intermolecular forces between the solute particles and water molecules.Explanation:Carbon dioxide, $\mathrm{CO_2}$, has polar $\mathrm{C=O}$ bonds.However, the molecule is linear and symmetrical, so its bond dipoles cancel out.Therefore, $\mathrm{CO_2}$ has no permanent dipole moment.Its solubility in water is not caused by dipole attraction between two polar molecules.Instead, it is caused by weak van der Waals forces, especially London dispersion forces and dipole-induced dipole forces.Polar water molecules induce temporary dipoles in the nonpolar $\mathrm{CO_2}$ molecules, allowing them to mix.Ionic attraction and covalent bonding are not relevant to this dissolving process.Answer:Option A. Van der Waal's forces.