Easy INTEGER +4 / -1 PYQ · JEE Mains 2021

40 g of glucose (Molar mass = 180) is mixed with 200 mL of water. The freezing point of solution is __________ K. (Nearest integer) [Given : Kf = 1.86 K kg mol$-$1; Density of water = 1.00 g cm$-$3; Freezing point of water = 273.15 K]

Answer (integer) 271

Solution

Molality = $${{\left( {{{40} \over {180}}} \right)mol} \over {0.2\,Kg}} = \left( {{{10} \over 9}} \right)$$ molal<br><br>$\Rightarrow \Delta {T_f} = {T_f} - {T_f}' = 1.86 \times {{10} \over 9}$<br><br>$\Rightarrow {T_f}' = 273.15 - 1.86 \times {{10} \over 9}$<br><br>= 271.08 K<br><br>$\simeq$ 271 K (nearest - integer)

About this question

Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws

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