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Derive the Relation Between the Elevation of Boiling Point and Molar Mass of Solute.

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Question

Derive the relation between the elevation of boiling point and molar mass of solute.

Sum
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Solution

The elevation in the boiling point is given by the expression `Δ"T"_"b" = "K"_"b"  ."m"` .....(1)

The molality is given by the expression m = `"W"_2/("M"_2 . "W"_1)`  ...(2)

Substitute equation (2) in equation (1)

`Δ"T"_"b" = "K"_"b"  . "W"_2/("M"_2  . "W"_1`

Hence, the expression for the molar mass of the solute is
 
`"M"_2 = ("K"_"b"  . "W"_2)/(Δ"T"_"b" . "W"_1)`
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2017-2018 (March)

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