(C) Concentration of $HCOOH = 0.5 \, mL \, L^{-1}$.Mass of $HCOOH = 0.5 \, mL \times 1.05 \, g \, mL^{-1} = 0.525 \, g \, L^{-1}$.Molar mass of $HCOOH

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(C) Concentration of $HCOOH = 0.5 \, mL \, L^{-1}$.Mass of $HCOOH = 0.5 \, mL \times 1.05 \, g \, mL^{-1} = 0.525 \, g \, L^{-1}$.Molar mass of $HCOOH = 46 \, g \, mol^{-1}$.Molality $(m) = \frac{0.525 \, g}{46 \, g \, mol^{-1} \times 1 \, kg} \approx 0.01141 \, mol \, kg^{-1}$.Using the formula $\Delta T_{f} = i K_{f} m$,we have $i = \frac{\Delta T_{f}}{K_{f} m}$.$i = \frac{0.0405}{1.86 \times 0.01141} \approx \frac{0.0405}{0.02122} \approx 1.908$.Thus,the Van't Hoff factor is nearly $1.9$.

Class 12 Chemistry Solutions Abnormal molecular mass

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The depression in freezing point observed for a formic acid solution of concentration $0.5 \, mL \, L^{-1}$ is $0.0405^{\circ} \, C$. The density of formic acid is $1.05 \, g \, mL^{-1}$. The Van't Hoff factor of the formic acid solution is nearly: (Given for water $K_{f} = 1.86 \, K \, kg \, mol^{-1}$)

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A
$0.8$
B
$1.1$
C
$1.9$
D
$2.4$

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The values of observed and calculated molecular weight of silver nitrate are $90$ and $170$ respectively. The degree of dissociation of silver nitrate is ......... $\%$.

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$2 \ g$ of benzoic acid $(C_6H_5COOH)$ dissolved in $25 \ g$ of benzene shows a depression in freezing point equal to $1.62 \ K$. The molal depression constant for benzene is $4.9 \ K \ kg \ mol^{-1}$. The percentage of benzoic acid in dimeric form is ......... $\%$.

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$20 \ g$ of naphthoic acid $(C_{11}H_8O_2)$ $(M_w = 172 \ g/mol)$ is dissolved in $50 \ g$ of benzene. The freezing point depression of $2 \ K$ is observed for the solution. The Van't Hoff factor $(i)$ will be ($K_f$ for benzene $= 1.72 \ K \ kg \ mol^{-1}$)

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The Van't Hoff factor $i$ for a $0.2 \ m$ aqueous solution of urea is

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$A$ $0.004 \ M$ solution of $Na_2SO_4$ is isotonic with a $0.010 \ M$ solution of glucose at the same temperature. The apparent degree of dissociation of $Na_2SO_4$ is $..... \ \%$.

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The values of observed and calculated molecular weight of silver nitrate are $90$ and $170$ respectively. The degree of dissociation of silver nitrate is ......... $\%$.

$2 \ g$ of benzoic acid $(C_6H_5COOH)$ dissolved in $25 \ g$ of benzene shows a depression in freezing point equal to $1.62 \ K$. The molal depression constant for benzene is $4.9 \ K \ kg \ mol^{-1}$. The percentage of benzoic acid in dimeric form is ......... $\%$.

$20 \ g$ of naphthoic acid $(C_{11}H_8O_2)$ $(M_w = 172 \ g/mol)$ is dissolved in $50 \ g$ of benzene. The freezing point depression of $2 \ K$ is observed for the solution. The Van't Hoff factor $(i)$ will be ($K_f$ for benzene $= 1.72 \ K \ kg \ mol^{-1}$)

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$A$ $0.004 \ M$ solution of $Na_2SO_4$ is isotonic with a $0.010 \ M$ solution of glucose at the same temperature. The apparent degree of dissociation of $Na_2SO_4$ is $..... \ \%$.

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