Freezing point of a 4 % aqueous solution of X | vedclass

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

Question

(A) The depression in freezing point is given by $\Delta T_f = K_f 	imes m$,where $m$ is the molality of the solution.Since the freezing points are e

Vedclass · Accepted Answer

$3$

Vedclass · Answer

(A) The depression in freezing point is given by $\Delta T_f = K_f 	imes m$,where $m$ is the molality of the solution.Since the freezing points are equal,$(\Delta T_f)_X = (\Delta T_f)_Y$,which implies $m_X = m_Y$.For a $4 \%$ aqueous solution of $X$,the mass of $X$ is $4 \ g$ in $96 \ g$ of water. Molality $m_X = \frac{4 	imes 1000}{A 	imes 96}$.For a $12 \%$ aqueous solution of $Y$,the mass of $Y$ is $12 \ g$ in $88 \ g$ of water. Molality $m_Y = \frac{12 	imes 1000}{M_Y 	imes 88}$.Equating the two: $\frac{4}{A 	imes 96} = \frac{12}{M_Y 	imes 88}$.Solving for $M_Y$: $M_Y = \frac{12 	imes 96 	imes A}{4 	imes 88} = \frac{3 	imes 96 	imes A}{88} = \frac{288 	imes A}{88} \approx 3.27 	imes A$.Rounding to the nearest integer,the molecular weight of $Y$ is $3A$.

Freezing point of a $4 \%$ aqueous solution of $X$ is equal to the freezing point of a $12 \%$ aqueous solution of $Y$. If the molecular weight of $X$ is $A$,then the molecular weight of $Y$ is ............. $A$.

Similar Questions

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

If the $K_f$ value of $H_2O$ is $1.86 \ K \ kg \ mol^{-1}$,the value of $\Delta T_f$ for a $0.1 \ m$ solution of a non-volatile solute is:

Lead storage battery contains $38\%$ by weight solution of $H_2SO_4$. The van't Hoff factor is $2.67$ at this concentration. The temperature in Kelvin at which the solution in the battery will freeze is $..........$ (Nearest integer). Given $K_f = 1.8 \, K \, kg \, mol^{-1}$.

During the depression in freezing point experiment, an equilibrium is established between the molecules of

$A$ solution of a nonvolatile solute is obtained by dissolving $1 \ g$ in $100 \ g$ of solvent,which decreases its freezing point by $0.3 \ K$. Calculate the cryoscopic constant of the solvent if the molar mass of the solute is $60 \ g \ mol^{-1}$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module