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(B) The freezing point depression $\Delta T_f$ is a colligative property,which depends on the molality $(m)$ of the solution. $\Delta T_f = K_f 	imes

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$6 \ g$ urea in $100 \ g \ H_2O$ and $18 \ g$ glucose in $100 \ g \ H_2O$

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(B) The freezing point depression $\Delta T_f$ is a colligative property,which depends on the molality $(m)$ of the solution. $\Delta T_f = K_f 	imes m$. For the freezing points to be equal,the molality of the two solutions must be equal. Molality $m = \frac{	ext{moles of solute}}{	ext{mass of solvent in kg}}$. For option $B$: Moles of urea $= \frac{6 \ g}{60 \ g/mol} = 0.1 \ mol$. Moles of glucose $= \frac{18 \ g}{180 \ g/mol} = 0.1 \ mol$. Since the mass of the solvent $(100 \ g \ H_2O)$ is the same for both,and the number of moles of solute is the same $(0.1 \ mol)$,the molality of both solutions is identical. Therefore,they will have the same freezing point.

Under identical conditions,which aqueous solutions have the same freezing point? (Molecular mass of urea $= 60 \ u$ and glucose $= 180 \ u$)

Similar Questions

If $6 \ g$ of solute dissolved in $100 \ g$ of water lowers the freezing point by $0.93 \ K$. What is the molar mass of the solute? $(K_{f} = 1.86 \ K \ kg \ mol^{-1})$

Calculate the molar mass of the solute when $1.5 \ g$ of a non-volatile solute is dissolved in $100 \ mL$ of a solvent having a density of $0.8 \ g \ mL^{-1}$,which lowers its freezing point by $0.75 \ K$. (Freezing point depression constant for the solvent is $5 \ K \ kg \ mol^{-1}$).

The freezing point of a solution prepared from $1.25 \ g$ of a non-electrolyte and $20 \ g$ of water is $271.9 \ K$. If the molar depression constant is $1.86 \ K \ kg \ mol^{-1}$,then the molar mass of the solute will be:

$6 \ g$ of a non-volatile,non-electrolyte $X$ dissolved in $100 \ g$ of water freezes at $-0.93^{\circ} C$. The molar mass of $X$ in $g \ mol^{-1}$ is ($K_f$ of $H_2O = 1.86 \ K \ kg \ mol^{-1}$)

If the $K_f$ value of $H_2O$ is $1.86$,what is the value of $\Delta T_f$ for a $0.1 \ m$ solution of a non-volatile solute?

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