Answer:
0.50mmHg
Explanation:
Raoult's law (Vapor pressure depression) is:
[tex]P_{solution} = X_{solvent} P^0_{solvent}[/tex]
Where P is vapour pressure of solution and vapour pressure of solvent and X is mole fraction of solvent.
Van't Hoff factor helps to know how many species comes from the dissolution of the compound in the solvent.
Assuming volume of solution is 1L, moles of LiCl in solution are:
0.62×1.92 = 1.19 moles of LiCl in solution
Moles of water in 1L are:
1L ≡ 1000g × (1mol / 18g) = 55.56mol H₂O
Mole fraction of water is:
55.56mol / (55.56mol + 1.19mol) = 0.979
Vapour pressure of solution is:
[tex]P_{solution} = 23.26mmHg[/tex]
That means vapour pressure depression is:
23.76mmHg - 23.26mmHg = 0.50mmHg
I hope it helps!
