Question

water and its properties quiz
cp chemistry a o / module 6: covalent compounds

1. which statement best describes what occurs when a polar molecule like so₂ is mixed with water?

so₂ dissolves and dissociates in water, forming dipole - dipole attractions with the water molecules.
so₂ dissolves in water and forms dipole - dipole attractions with the water molecules.
so₂ dissolves and dissociates in water, forming ion - dipole attractions with the water molecules.
so₂ does not dissolve in water.

Explanation:

To solve this, we analyze each option:

1. \( \text{SO}_2 \) is a polar molecule (bent structure, dipole moment). Water is polar. "Like dissolves like" applies. \( \text{SO}_2 \) reacts with water: \( \text{SO}_2 + \text{H}_2\text{O}

ightleftharpoons \text{H}_2\text{SO}_3 \), which dissociates into ions (\( \text{H}^+ \), \( \text{HSO}_3^- \), etc.). When \( \text{SO}_2 \) dissolves and dissociates, the resulting ions form ion - dipole attractions with polar water molecules (ions from dissociation, dipole from \( \text{H}_2\text{O} \)).

1. First option: Dipole - dipole is incorrect because after dissociation, ions are present (ion - dipole, not just dipole - dipole between \( \text{SO}_2 \) and \( \text{H}_2\text{O} \) post - reaction).
2. Second option: Says \( \text{SO}_2 \) dissolves but not dissociates, but \( \text{SO}_2 \) does react/dissociate in water, so wrong.
3. Fourth option: \( \text{SO}_2 \) is polar and reacts with water, so it does dissolve, wrong.

Answer:

\( \text{SO}_2 \) dissolves and dissociates in water, forming ion - dipole attractions with the water molecules. (The option with this statement, likely the third radio - button option in the image)