Question

which statement best describes how dynamic equilibrium relates to a saturated solution of sodium chloride?
the concentration of the dissolved particles remains constant.
no more solid dissolves in a saturated solution.
each second, the amount of solid sodium chloride that dissolves equals the amount of solid sodium chloride that recrystallizes.
each second, solid sodium chloride dissolves and solid sodium chloride recrystallizes.

Explanation:

To determine the correct statement about dynamic equilibrium in a saturated NaCl solution, we analyze each option:

• Option 1: "Concentration remains constant" describes a result of equilibrium, not the dynamic process itself.
• Option 2: "No more solid dissolves" is incorrect—dissolution and recrystallization still occur (dynamic equilibrium), just at equal rates.
• Option 3: Dynamic equilibrium in a saturated solution means the rate of dissolution (solid → dissolved) equals the rate of recrystallization (dissolved → solid) per unit time (e.g., per second). This directly defines the dynamic balance.
• Option 4: Stating "dissolves and recrystallizes" lacks the key detail that their rates are equal, which is essential for dynamic equilibrium.

Answer:

C. Each second, the amount of solid sodium chloride that dissolves equals the amount of solid sodium chloride that recrystallizes.