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An aqueous solution containing 288gm of a non-volatile compound having the stochiometric composition `"C"_("X")"H"_("2X")"O"_("X")` in 90gm water boils at `101.24^(@)"C"` at 1.00 atmospheric pressure. What is the molecular formula? `"K"_("b")("H"_(2)"O")=0.512" K mol"^(-1) "kg"" T"_("b")("H"_(2)"O")=100^(@)"C"`

Answer» Elevation in B.P `=101.24-100=1.24^(@)"C"`
`Delta "T"_("b")="K"_("b")xx"i"xx"molality" implies1.24=0.512xx288/"m"xx1000/90 (therefore"i"=1)`
`therefore "m"=1321.2"gm mol"^(-1)`
molar mass of `"C"_("X")"H"_("2X")"O"_("X")=12"x"+1xx2"x"+16"x"=30"x"`
`therefore "x"=44`
Hence the molecular formula is `="C"_("44")"H"_("88")"O"_("44")`


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