(C) Molar mass of $Na_2SO_4 = (2 \times 23) + 32 + (4 \times 16) = 142 \ g \ mol^{-1}$.Van't Hoff factor $(i)$ for $Na_2SO_4 \to 2Na^+ + SO_4^{2-}$ is

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(C) Molar mass of $Na_2SO_4 = (2 \times 23) + 32 + (4 \times 16) = 142 \ g \ mol^{-1}$.Van't Hoff factor $(i)$ for $Na_2SO_4 \to 2Na^+ + SO_4^{2-}$ is $i = 1 + (n-1)\alpha$,where $n=3$ and $\alpha = 0.815$.$i = 1 + (3-1) \times 0.815 = 1 + 2 \times 0.815 = 2.63$.Freezing point depression formula: $\Delta T_f = i \times K_f \times m$.$3.82 = 2.63 \times 1.86 \times \left( \frac{5 / 142}{x / 1000} \right)$.$3.82 = 2.63 \times 1.86 \times \frac{5000}{142 \times x}$.$x = \frac{2.63 \times 1.86 \times 5000}{142 \times 3.82} \approx 45.07 \ g$.

Class 12 Chemistry Solutions Colligative properties of electrolyte

$5 \ g$ of $Na_2SO_4$ was dissolved in $x \ g$ of $H_2O$. The change in freezing point was found to be $3.82 \ ^oC$. If $Na_2SO_4$ is $81.5 \%$ ionised,the value of $x$ ($K_f$ for water $= 1.86 \ ^oC \ kg \ mol^{-1}$) is approximately .............. $g$ (molar mass of $S = 32 \ g \ mol^{-1}$ and that of $Na = 23 \ g \ mol^{-1}$)

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$15$
B
$25$
C
$45$
D
$65$

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The freezing point depression constant for water is $1.86 \, ^oC \, kg \, mol^{-1}.$ If $5.00 \, g$ of $Na_2SO_4$ is dissolved in $45.0 \, g$ of $H_2O,$ the freezing point is lowered by $3.82 \, ^oC.$ Calculate the van't Hoff factor for $Na_2SO_4.$

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Consider the following solutions:
$I$. $1 \ M$ glucose $(aq.)$
$II$. $1 \ M$ sodium chloride $(aq.)$
$III$. $1 \ M$ acetic acid in benzene
$IV$. $1 \ M$ ammonium phosphate $(aq.)$

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$17.4\%\, (w/v)$ $K_2SO_4$ $(Mw=174\, g/mol)$ solution at $27\, ^\circ C$ is isotonic to $4\%\, (w/v)\, NaOH$ solution at the same temperature. If $NaOH$ is $100\%$ ionized,what is the $\%$ ionization of $K_2SO_4$ in aqueous solution .......... $\%$.

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At higher altitude,the boiling point of water is $95\,^oC$. The amount of $NaCl$ added to $1\,kg$ of water $(K_b = 0.52\,K\,kg\,mol^{-1})$ in order to raise the boiling point of the solution to $100\,^oC$ (assume $90\%$ ionisation of $NaCl$) is .......... $g$.

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Which of the following solutions will have the highest boiling point?

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The freezing point depression constant for water is $1.86 \, ^oC \, kg \, mol^{-1}.$ If $5.00 \, g$ of $Na_2SO_4$ is dissolved in $45.0 \, g$ of $H_2O,$ the freezing point is lowered by $3.82 \, ^oC.$ Calculate the van't Hoff factor for $Na_2SO_4.$

Consider the following solutions:$I$. $1 \ M$ glucose $(aq.)$$II$. $1 \ M$ sodium chloride $(aq.)$$III$. $1 \ M$ acetic acid in benzene$IV$. $1 \ M$ ammonium phosphate $(aq.)$

$17.4\%\, (w/v)$ $K_2SO_4$ $(Mw=174\, g/mol)$ solution at $27\, ^\circ C$ is isotonic to $4\%\, (w/v)\, NaOH$ solution at the same temperature. If $NaOH$ is $100\%$ ionized,what is the $\%$ ionization of $K_2SO_4$ in aqueous solution .......... $\%$.

At higher altitude,the boiling point of water is $95\,^oC$. The amount of $NaCl$ added to $1\,kg$ of water $(K_b = 0.52\,K\,kg\,mol^{-1})$ in order to raise the boiling point of the solution to $100\,^oC$ (assume $90\%$ ionisation of $NaCl$) is .......... $g$.

Which of the following solutions will have the highest boiling point?

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Consider the following solutions:
$I$. $1 \ M$ glucose $(aq.)$
$II$. $1 \ M$ sodium chloride $(aq.)$
$III$. $1 \ M$ acetic acid in benzene
$IV$. $1 \ M$ ammonium phosphate $(aq.)$