(B) Given: $(T_f)_s = 271.9 \ K$,$w = 1.25 \ g$,$W = 20 \ g$,$K_f = 1.86 \ K \ kg \ mol^{-1}$,$T_0 = 273 \ K$. $\Delta T_f = T_0 - (T_f)_s = 273 - 271

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(B) Given: $(T_f)_s = 271.9 \ K$,$w = 1.25 \ g$,$W = 20 \ g$,$K_f = 1.86 \ K \ kg \ mol^{-1}$,$T_0 = 273 \ K$. $\Delta T_f = T_0 - (T_f)_s = 273 - 271.9 = 1.1 \ K$. The formula for depression in freezing point is: $\Delta T_f = \frac{w \times 1000 \times K_f}{M_w \times W}$. Rearranging for molar mass $(M_w)$: $M_w = \frac{w \times 1000 \times K_f}{\Delta T_f \times W}$. Substituting the values: $M_w = \frac{1.25 \times 1000 \times 1.86}{1.1 \times 20}$. $M_w = \frac{2325}{22} = 105.68 \ g \ mol^{-1}$.

Class 12 Chemistry Solutions Depression of freezing point of the solvent

Medium

The freezing point of a solution containing $1.25 \ g$ of a non-electrolyte solute in $20 \ g$ of water is $271.9 \ K$. What is the molar mass of the solute? (Given: $K_f$ for water = $1.86 \ K \ kg \ mol^{-1}$,Freezing point of pure water = $273 \ K$)

A
$109.99$
B
$105.68$
C
$215.36$
D
$318.69$

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Depression of freezing point of the solvent

Which of the following solutions will have the lowest freezing point?

Medium

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$A$ solution of $36 \ g$ of glucose $(C_6H_{12}O_6)$ in $1000 \ g$ of water is cooled to $-0.5 \ ^\circ C$. How many grams of ice would have separated from the solution? (Given: $K_f = 1.86 \ K \ kg \ mol^{-1}$)

Medium

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The freezing point of a $4 \%$ by weight aqueous solution of $A$ is equal to the freezing point of a $10 \%$ by weight aqueous solution of $B$. If the molecular weight of $A$ is $60$,then the molecular weight of $B$ is:

Medium

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The freezing point of a diluted milk sample is found to be $-0.2\ ^\circ C$,while it should be $-0.5\ ^\circ C$ for pure milk. How much water has been added to pure milk to make the diluted sample?

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$K_{f}$ (water) $= 1.86 \ K \ kg \ mol^{-1}$. The temperature at which ice begins to separate from a mixture of $10$ mass $\%$ ethylene glycol is (in $^{\circ} C$)

EasyWBJEE 2020

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The freezing point of a solution containing $1.25 \ g$ of a non-electrolyte solute in $20 \ g$ of water is $271.9 \ K$. What is the molar mass of the solute? (Given: $K_f$ for water = $1.86 \ K \ kg \ mol^{-1}$,Freezing point of pure water = $273 \ K$)

Similar Questions

Which of the following solutions will have the lowest freezing point?

$A$ solution of $36 \ g$ of glucose $(C_6H_{12}O_6)$ in $1000 \ g$ of water is cooled to $-0.5 \ ^\circ C$. How many grams of ice would have separated from the solution? (Given: $K_f = 1.86 \ K \ kg \ mol^{-1}$)

The freezing point of a $4 \%$ by weight aqueous solution of $A$ is equal to the freezing point of a $10 \%$ by weight aqueous solution of $B$. If the molecular weight of $A$ is $60$,then the molecular weight of $B$ is:

The freezing point of a diluted milk sample is found to be $-0.2\ ^\circ C$,while it should be $-0.5\ ^\circ C$ for pure milk. How much water has been added to pure milk to make the diluted sample?

$K_{f}$ (water) $= 1.86 \ K \ kg \ mol^{-1}$. The temperature at which ice begins to separate from a mixture of $10$ mass $\%$ ethylene glycol is (in $^{\circ} C$)

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