Question

A mixture of ethyl iodide (b.p. 72.3) and water boils at 63.7 C. What weight of ethyl iodide would be carried over by 1 gm of steam during steam distillation

Answer 1

Do you have the vapor pressure at the appropriate temperature in your problem.

Answer 2

You need only to know the vapor pressure of water at that b.p. which is ~ 179 mm hg, so the (vapor pressure of C2H5I = 760 - 179 )and since you know (M.W. of H2O = 18 g/mol, & M.W. C2H5I = 156 g/mol), you just apply the equation:
grams H2O M.W. H2O × P H2O
---------------------- = --------------------------------------- = 28.13 grams C2H5I
grams C2H5I M.W. C2H5I × P C2H5I