The given question is incomplete. The complete question is:
When 19 mg of a certain molecular compound X are dissolved in 200 g of benzonitrile , the freezing point of the solution is measured to be . Calculate the molar mass of X. Freezing point of pure benzonitrile =
Answer: Molar mass of X is 1271 grams
Explanation:
Depression in freezing point =
Mass of solute (X) = 19 g
Mass of solvent (benzonitrile) = 200.0 g = 0.2 kg (1 kg = 1000 g)
Formula used :
where,
= change in freezing point =
i = Van't Hoff factor = 1
= freezing point constant = 5.35 K.kg/mole
m = molality
Now put all the given values in this formula, we get
Thus molar mass of X is 1271 grams