1. Tardigrade
  2. Question
  3. Chemistry
  4. The vapour pressure of pure liquid solvent is 0.50 atm. When a non-volatile solute B is added to the solvent, its vapour pressure drops to 0.30 atm. Thus, mole fraction of the component B is

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Q. The vapour pressure of pure liquid solvent is $0.50\, atm$. When a non-volatile solute $B$ is added to the solvent, its vapour pressure drops to $0.30\, atm$. Thus, mole fraction of the component $B$ is

Solutions

Solution:

Binary mixture contains non-volatile solute (B) in volatile solvent
By Raoult's law, relative decrease in vapour pressure =
$\frac{\Delta P}{P^{o}}=\chi_{\text{Solute}}$
$\Rightarrow \frac{0.30}{0.50}=\chi_{\text{Solute}}$
$\therefore \chi_{\text{Solute}}=0.6$