Question

Given the formula for depression of freezing point: \[ \Delta T_f = K_f \cdot m \] where \( \Delta T_f \) is the depression of freezing point, \( K_f \) is the freezing point depression constant, and \( m \) is the molality, calculate the value of \( m \).

• A. \( m = \frac{\Delta T_f}{K_f} \)
• B. \( m = \frac{K_f}{\Delta T_f} \)
• C. \( m = K_f \cdot \Delta T_f \)
• D. \( m = \frac{\Delta T_f}{K_f^2} \)

Hint:

When using the depression of freezing point formula, rearrange the equation to solve for the desired variable. In this case, the molality \( m \) can be calculated by dividing the depression of freezing point \( \Delta T_f \) by the freezing point depression constant \( K_f \).

Answer 1

The Correct Option is A

The freezing point depression is quantified by the equation: \[ \Delta T_f = K_f \cdot m \] In this formula:
\( \Delta T_f \) represents the change in freezing point,
\( K_f \) denotes the freezing point depression constant, and
\( m \) signifies the molality of the solution.

Step 1: Calculate Molality The molality \( m \) can be determined by rearranging the formula: \[ m = \frac{\Delta T_f}{K_f} \] This equation illustrates that molality is directly proportional to the freezing point depression and inversely proportional to the freezing point depression constant.

Therefore, the accurate expression is \( {m = \frac{\Delta T_f}{K_f}} \).