Question:
A non-volatile solute, ?A? tetramerises in water to the extent of 80%. 2.5 g of ?A? in 100 g of water, lowers the freezing point by 0.3 ?C. the molar mass of ? in mol L-1 is (Kf for water = 1.86 K kg mol-1)
A non-volatile solute, ?A? tetramerises in water to the extent of 80%. 2.5 g of ?A? in 100 g of water, lowers the freezing point by 0.3 ?C. the molar mass of ? in mol L-1 is (Kf for water = 1.86 K kg mol-1)
Updated On: Mar 25, 2024
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The Correct Option is C
Solution and Explanation
$\alpha=\frac{80}{100}=0.8$
$\alpha=\frac{1-i}{1-\frac{1}{n}}=\frac{1-i}{1-\frac{1}{4}}$
$0.8=\frac{1-i}{\frac{3}{4}}$
$i=0.4$
$\Delta T_{f}=0.3$
$\Delta T_{f}=\frac{i\times k_{f}\times w_{2}\times1000}{M_{2}\times100}$
$M_{2}=\frac{0.4\times1.86\times2.5\times10}{0.3}$
$M_{2}=62 \, g\, mol^{-1}$
$\alpha=\frac{1-i}{1-\frac{1}{n}}=\frac{1-i}{1-\frac{1}{4}}$
$0.8=\frac{1-i}{\frac{3}{4}}$
$i=0.4$
$\Delta T_{f}=0.3$
$\Delta T_{f}=\frac{i\times k_{f}\times w_{2}\times1000}{M_{2}\times100}$
$M_{2}=\frac{0.4\times1.86\times2.5\times10}{0.3}$
$M_{2}=62 \, g\, mol^{-1}$
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Concepts Used:
Solutions
A solution is a homogeneous mixture of two or more components in which the particle size is smaller than 1 nm.
For example, salt and sugar is a good illustration of a solution. A solution can be categorized into several components.
Types of Solutions:
The solutions can be classified into three types:
- Solid Solutions - In these solutions, the solvent is in a Solid-state.
- Liquid Solutions- In these solutions, the solvent is in a Liquid state.
- Gaseous Solutions - In these solutions, the solvent is in a Gaseous state.
On the basis of the amount of solute dissolved in a solvent, solutions are divided into the following types:
- Unsaturated Solution- A solution in which more solute can be dissolved without raising the temperature of the solution is known as an unsaturated solution.
- Saturated Solution- A solution in which no solute can be dissolved after reaching a certain amount of temperature is known as an unsaturated saturated solution.
- Supersaturated Solution- A solution that contains more solute than the maximum amount at a certain temperature is known as a supersaturated solution.