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AP EAMCET · Chemistry · Solutions

\(6 \mathrm{~g}\) of a mixture of naphthalene \(\left(\mathrm{C}_{10} \mathrm{H}_8\right)\) and anthracene \(\left(\mathrm{C}_{14} \mathrm{H}_{10}\right)\) is dissolved in 300 gram of benzene. If the depression in freezing point is \(0.70 \mathrm{~K}\), the composition of naphthalene and anthracene in the mixture respectively in \(\mathrm{g}\) are (molal depression constant of benzene is \(5.1 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\) )

  1. A \(2.60,3.40\)
  2. B \(3.40,2.60\)
  3. C \(2.90,3.10\)
  4. D \(3.10,2.90\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(3.40,2.60\)

Step-by-step Solution

Detailed explanation

Given, weight of solvent \(=300 \mathrm{~g}\) \(\begin{aligned} \text {Molality } & =\frac{\text { moles of solute }}{\text { weight of solvent }(\mathrm{kg})} \\ K_f & =5.1 \mathrm{~K} \mathrm{~kg} / \mathrm{mol} \end{aligned}\) Depression in freezing point,…