Question

The concentration units independent of temperature would be

• A. Normality
• B. Mass-volume percent
• C. Molality
• D. Molarity

Answer 1

The Correct Option is C

To determine which concentration unit is independent of temperature, let's analyze each option:

• Normality: Normality is defined as the number of gram equivalent weights of solute per liter of solution. It depends on the volume of the solution, which can change with temperature. Hence, normality is temperature-dependent.
• Mass-volume percent: This unit represents the mass of solute per 100 mL of solution. Since it involves the volume of the solution, it is also temperature-dependent.
• Molality: Molality is defined as the number of moles of solute per kilogram of solvent. It does not involve the volume of the solution but rather the mass of the solvent. Since mass is invariant to temperature, molality is temperature-independent.
• Molarity: Molarity is defined as the number of moles of solute per liter of solution. As it involves the volume of the solution, it is temperature-dependent.

From the analysis above, we can conclude that molality is the only concentration unit that is not affected by changes in temperature.