Benzene and toluene form nearly ideal solution.The vapour pressure of pure toluene is 22 torr at 20 degree celcius for equimolar mixture of benzene and toluene at 20 degree celcius the vapour pressure of toluene is.?

1 Answer
Truong-Son N.
Apr 11, 2018

Mixing volatile solutes together follows Raoult's law:

#P_A = chi_(A(l))P_A^"*"#,

where:

  • #P_A# is the vapor pressure of the solvent in the solution.
  • #P_A^"*"# is that of the solvent by itself.
  • #chi_(A(l))# is the mol fraction of the solvent in the solution phase.

You have some info you do NOT need... in an ideal solution there is no interaction between particles, so #P_"tol"# after forming the solution without stirring is precisely what it is after mixing well.

#color(blue)(P_"tol") = chi_("Tol"(l))P_"tol"^"*"#

#= "0.500 mols" cdot "22 torr"#

#=# #color(blue)"11 torr"#

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