The relative lowering of vapor pressure of an aqueous solution containing a non-volatile solute is 0.0225. The mole fraction of the non-volatile solute is:
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For dilute solutions, the mole fraction of solute can be approximated as the relative lowering of vapor pressure.
Relative lowering of vapor pressure is given by Raoult’s Law:
\[
\frac{P_0 - P}{P_0} = X_B
\]
where:
- \( P_0 \) is the vapor pressure of pure solvent,
- \( P \) is the vapor pressure of the solution,
- \( X_B \) is the mole fraction of the solute.
Since relative lowering of vapor pressure is given as 0.0225, we directly get:
\[
X_B = 0.0225
\]