Question

A very dilute solution is prepared by dissolving \( x_1 \) mole of solute in \( x_2 \) mole of a solvent. The mole fraction of solute is approximately equal to:

• A. \( \frac{x_1}{x_2}\)
• B. \( \frac{x_2}{x_1}\)
• C. \( 1 - \frac{x_1}{x_2}\)
• D. \( \frac{1}{x_2}\)

Hint:

For dilute solutions, the mole fraction of solute is approximately \( \frac{x_1}{x_2} \), as \( x_1 \) is much smaller than \( x_2 \).

Answer 1

The Correct Option is A

Step 1: Understanding mole fraction. - The mole fraction of solute (\( X_s \)) is calculated by: \[ X_s = \frac{x_1}{x_1 + x_2} \] - For very dilute solutions, where \( x_1 \) is much smaller than \( x_2 \), the mole fraction of solute can be approximated by: \[ X_s \approx \frac{x_1}{x_2} \]
Step 2: Selecting the correct option. Since the mole fraction of solute simplifies to \( \frac{x_1}{x_2} \) for very dilute solutions, the correct answer is (A) \( \frac{x_1}{x_2} \).