What describes an insoluble substance?

What describes an insoluble substance?

• A. A substance that dissolves easily.
• B. A substance that does not dissolve in a particular solvent.
• C. A solvent that is insoluble in water.
• D. A solute that expands in a solvent.

Answer: (B)

Insolubility means a substance does not dissolve in a given solvent under the conditions shown. Solubility is about how much of a solute can dissolve in a solvent before the solution is saturated, and if a substance is insoluble, it remains undissolved when mixed with that solvent (often forming a separate layer or a suspension). This is why the description that fits an insoluble substance is: it does not dissolve in a particular solvent. Keep in mind that solubility depends on the solvent and conditions like temperature. For example, oil is insoluble in water because the two substances interact poorly due to polarity differences. The other options describe things that aren’t about a substance failing to dissolve in a solvent—dissolving easily means it’s soluble, a solvent being insoluble in water describes a property of the solvent rather than the solute, and expansion in a solvent isn’t the defining feature of insolubility.

Insolubility means a substance does not dissolve in a given solvent under the conditions shown. Solubility is about how much of a solute can dissolve in a solvent before the solution is saturated, and if a substance is insoluble, it remains undissolved when mixed with that solvent (often forming a separate layer or a suspension). This is why the description that fits an insoluble substance is: it does not dissolve in a particular solvent.

Keep in mind that solubility depends on the solvent and conditions like temperature. For example, oil is insoluble in water because the two substances interact poorly due to polarity differences. The other options describe things that aren’t about a substance failing to dissolve in a solvent—dissolving easily means it’s soluble, a solvent being insoluble in water describes a property of the solvent rather than the solute, and expansion in a solvent isn’t the defining feature of insolubility.