JEE Mains · Chemistry · STD 12 -1. Solution and colligative properties
Solute \(A\) associates in water. When \(0.7\, g\) of solute \(A\) is dissolved in \(42.0\, g\) of water, it depresses the freezing point by \(0.2^{\circ} C\). The percentage association of solute \(A\) in water, is \(.....\,\%\) [Given : Molar mass of \(A =93\, g\, mol ^{-1}\). Molal depression constant of water is \(1.86\, K \,kg\, mol ^{-1}\) ]
- A \(50\)
- B \(60\)
- C \(70\)
- D \(80\)
Answer & Solution
Correct Answer
(D) \(80\)
Step-by-step Solution
Detailed explanation
\(\Delta T = i \,k _{ f } \times m\) \(0.2= i \times 1.86 \times \frac{0.7}{93} \times \frac{1000}{42}\) \(i =\frac{0.2 \times 93 \times 6}{1.86 \times 100}\) \(i =0.60\) \(2 A \quad \rightleftharpoons A _{2}\) \(1-\alpha\) \(i =1-\alpha+\frac{\alpha}{2}\)…
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