A 5% solution (by mass) of cane sugar in wate | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The depression in freezing point is given by $\Delta T_f = K_f 	imes m$,where $m$ is the molality.For a $5\%$ solution (by mass),the molality $m

Vedclass · Accepted Answer

$269.07$

Vedclass · Answer

(C) The depression in freezing point is given by $\Delta T_f = K_f 	imes m$,where $m$ is the molality.For a $5\%$ solution (by mass),the molality $m = \frac{w_2 	imes 1000}{M_2 	imes w_1}$.Since the percentage by mass is the same $(5\%)$,the molality is inversely proportional to the molar mass $(M_2)$ of the solute.$\Delta T_f \propto \frac{1}{M_2}$.For cane sugar $(M_1 = 342 \ g/mol)$: $\Delta T_{f1} = 273.15 - 271 = 2.15 \ K$.For glucose $(M_2 = 180 \ g/mol)$: $\Delta T_{f2} = \Delta T_{f1} 	imes \frac{M_1}{M_2}$.$\Delta T_{f2} = 2.15 	imes \frac{342}{180} = 2.15 	imes 1.9 = 4.085 \ K$.The freezing point of the glucose solution $= 273.15 - 4.085 = 269.065 \ K \approx 269.07 \ K$.

$A$ $5\%$ solution (by mass) of cane sugar in water has a freezing point of $271 \ K$ and the freezing point of pure water is $273.15 \ K$. The freezing point of a $5\%$ solution (by mass) of glucose in water is ............. $K$.

Similar Questions

Find the freezing point depression of a solution having molality $0.25 \ mol \ kg^{-1}$. $(K_{f} = 4.0 \ K \ kg \ mol^{-1})$ (in $K$)

When $4.5 \ g$ of a non-electrolyte solute is dissolved in $100 \ g$ of water,the freezing point of the solution is lowered by $0.465^o C$. The molar mass of the solute is ....... $g/mol$. (Given $K_f = 1.86 \ K \ kg \ mol^{-1}$)

Which of the following aqueous solutions has the highest freezing point?

Find the depression in freezing point of a solution when $3.2 \ g$ of a non-volatile solute with a molar mass of $128 \ g \ mol^{-1}$ is dissolved in $80 \ g$ of solvent,given that the cryoscopic constant of the solvent is $4.8 \ K \ kg \ mol^{-1}$. (in $K$)

What is observed during the depression of freezing point?

Vedclass Test Series

Exam Paper Generator

Online Exam Module