Question

The increase in the temperature of the aqueous solution will result in decrease of its:

• A. \(\text{weight \% of the solute}\)
• B. \(\text{mole fraction of the solute}\)
• C. \(\text{molarity}\)
• D. \(\text{molality}\)

Hint:

Molarity (\( M \)) decreases with increasing temperature because the solution volume expands as it heats up.

Answer 1

The Correct Option is C

Understanding Temperature Effects on Solution Concentration

Step 1: Molarity and Temperature Effects 

Molarity (\( M \)) is calculated as:

\[ M = \frac{\text{moles of solute}}{\text{liters of solution}} \]

As temperature increases, the volume of the solution expands, leading to a decrease in molarity.

Step 2: Explanation of Incorrect Options

Weight % (A) and Mole fraction (B): These are independent of solution volume and are not significantly affected by temperature changes.

Molality (D): Defined per kg of solvent, molality remains unaffected by temperature changes.

Step 3: Selecting the Correct Option

Since molarity is volume-dependent, the correct answer is: (C) Molarity