JEE Main 2022 · 29 Jul · Shift 2 · Chemistry Q83

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ChemistryInteger+4 / -1Question 83 of 90

1.80 g of solute A was dissolved in 62.5 cm $^3$ of ethanol and freezing point of the solution was found to be 155.1 K. The molar mass of solute A is _______ g mol $^{-1}$ .

[Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g cm $^{-3}$ . Freezing point depression constant of ethanol is 2.00 K kg mol $^{-1}$ ]

Your answer

Answer and worked solution

Official answer: 80

Solvent $62.5\times0.80=50$ g. $\Delta T_f=0.9=2.00\times\dfrac{1.80/M}{0.050}$ , so $M=80$ g/mol.

Answer: 80

Topics:Colligative properties

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JEE Main 2022 · 29 Jul · Shift 2, Chemistry question 83