The solubility of a salt refers to
A) the concentration of all ions in the solution.
B) how much of a salt will dissolve.
C) the equilibrium constant associated with a solubility equilibrium.
D) how many ions a salt dissociates into.
The Correct Answer and Explanation is:
Correct Answer: B) how much of a salt will dissolve.
Explanation
Solubility is a fundamental concept in chemistry that refers to the ability of a substance (solute) to dissolve in a solvent, forming a homogeneous solution. When discussing the solubility of a salt, the term specifically indicates how much of the salt can dissolve in a given amount of solvent, usually water, at a specific temperature and pressure, to form a saturated solution.
A saturated solution is one in which no more solute can dissolve under the given conditions, meaning the solution is in a dynamic equilibrium with undissolved salt. At this point, the rate of dissolution of the salt equals the rate of precipitation.
Option B is correct because it directly addresses the core idea of solubility—the maximum amount of salt that dissolves to form a stable solution at equilibrium. This value is typically expressed in units like grams per 100 mL of water or in mol/L (molarity).
Let’s briefly examine the incorrect options:
- Option A is incorrect because the solubility doesn’t refer to the concentration of all ions, but only to the maximum amount of the salt that dissolves.
- Option C confuses solubility with the solubility product constant (Ksp), which is related but not the same. Ksp is a mathematical representation of the equilibrium concentrations of the ions in a saturated solution, not the solubility itself.
- Option D refers to the dissociation behavior of salts (e.g., NaCl dissociates into Na⁺ and Cl⁻), which affects ionic concentrations but doesn’t define how much of the salt will dissolve.
In conclusion, the solubility of a salt is best described by how much of it can dissolve in water to reach equilibrium. This makes Option B the correct and most accurate answer.
