(C) Given: Degree of association $\alpha = 80\% = 0.8$ and $n = 4$ (for tetramerization). Van't Hoff factor $i = 1 + (\frac{1}{n} - 1)\alpha = 1 + (\f

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(C) Given: Degree of association $\alpha = 80\% = 0.8$ and $n = 4$ (for tetramerization). Van't Hoff factor $i = 1 + (\frac{1}{n} - 1)\alpha = 1 + (\frac{1}{4} - 1) \times 0.8 = 1 - 0.6 = 0.4$. Depression in freezing point $\Delta T_f = i \times K_f \times m$. $0.3 = 0.4 \times 1.86 \times \frac{2.5 \times 1000}{M_A \times 100}$. $0.3 = 0.4 \times 1.86 \times \frac{25}{M_A}$. $M_A = \frac{0.4 \times 1.86 \times 25}{0.3} = \frac{18.6}{0.3} = 62 \text{ g mol}^{-1}$.

Class 12 Chemistry Solutions Abnormal molecular mass

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$A$ non-volatile solute '$A$' tetramerizes in water to the extent of $80\%$. $2.5 \text{ g}$ of '$A$' in $100 \text{ g}$ of water lowers the freezing point by $0.3^\circ \text{C}$. The molar mass of $A$ in $\text{g mol}^{-1}$ is ($K_f$ for water $= 1.86 \text{ K kg mol}^{-1}$)

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In a solution of sulfur in carbon disulfide,$80 \%$ of the sulfur exists as $S_8$ and the remaining exists as $S_2$. The van't Hoff factor '$i$' will be:

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When $12.2 \ g$ of benzoic acid is dissolved in $100 \ g$ of water,the freezing point of the solution was found to be $-0.93^{\circ} C$ $(K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1})$. The number $(n)$ of benzoic acid molecules associated (assuming $100 \ \%$ association) is ........ .

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$A$ non-volatile solute '$A$' tetramerizes in water to the extent of $80\%$. $2.5 \text{ g}$ of '$A$' in $100 \text{ g}$ of water lowers the freezing point by $0.3^\circ \text{C}$. The molar mass of $A$ in $\text{g mol}^{-1}$ is ($K_f$ for water $= 1.86 \text{ K kg mol}^{-1}$)

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Assertion : The molecular weight of acetic acid determined by depression in freezing point method in benzene and water was found to be different.Reason : Water is polar and benzene is nonpolar.

The experimentally determined molar mass of a non-volatile solute, $BaCl_2$, in water by Cottrell's method, is

Calculate the van't Hoff factor $(i)$ for an aqueous solution of $0.02 \text{ m}$ formic acid if it freezes at $-0.045^{\circ}\text{C}$. Given: $K_f = 1.86 \text{ K kg mol}^{-1}$ and the freezing point of pure water $= 0^{\circ}\text{C}$.

In a solution of sulfur in carbon disulfide,$80 \%$ of the sulfur exists as $S_8$ and the remaining exists as $S_2$. The van't Hoff factor '$i$' will be:

When $12.2 \ g$ of benzoic acid is dissolved in $100 \ g$ of water,the freezing point of the solution was found to be $-0.93^{\circ} C$ $(K_{f}(H_{2}O) = 1.86 \ K \ kg \ mol^{-1})$. The number $(n)$ of benzoic acid molecules associated (assuming $100 \ \%$ association) is ........ .

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Assertion : The molecular weight of acetic acid determined by depression in freezing point method in benzene and water was found to be different.
Reason : Water is polar and benzene is nonpolar.