a mixture of compound $1+2$ was studied at t$=110$ c$.$ the vapor pressures are given below. the activity coefficients measured at x$1=0\mathrm{.}36$ and y$1=4\mathrm{.}06$ and y$2=1\mathrm{.}42.$ what value do you determine for a$12$ from the one parameter margules model? compound $(1)813$ mmhg psat compound $(2)566$ mmhg psat