Asolution was prepared by dissolving 2.2 g of an unknown solute in 16.7 g of ccl4. a thermal analysis was performed for this solution and it was found that its initial freezing point was – 28.7°c. a reliable source in the bibliography states that for ccl4, t°f = – 22.9°c, and its freezing point lowering constant is kf = 29.9°c/m. calculate the molar mass of the unknown solute.

Molar mass of unknown solute is 679 g/mol

Explanation:

Let us assume that the solute is a non-electrolyte.

For a solution with non-electrolyte solute remains dissolved in it -

Depression in freezing point of solution,

where, m is molality of solute in solution and is cryogenoscopic constant of solvent.

Here

If molar mass of unknown solute is M g/mol then-

So,

so, M = 679 g/mol

the answer is 75.0%.