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COMEDK · Chemistry · 17. Solutions

An aqueous solution which contains \(42 \%\) by weight ( \(\mathrm{w} / \mathrm{W}\) ) of a volatile liquid " A " of molar mass of \(140 \mathrm{~g} / \mathrm{mol}\), has a vapour pressure of 2141.4 mm of Hg at \(37^{\circ} \mathrm{C}\). What is the vapour pressure of the pure liquid "A"? Vapour pressure of water at \(37^{\circ} \mathrm{C}\) is 2019.1 mm .

  1. A 293 nm
  2. B 2519.2 nm
  3. C 3455.0 nm
  4. D 2356.4 nm
Verified Solution

Answer & Solution

Correct Answer

(C) 3455.0 nm

Step-by-step Solution

Detailed explanation

Let the total mass of the solution be \(100 \text{ g}\). Mass of solute A = \(42 \text{ g}\). Mass of solvent (water) = \(100 - 42 = 58 \text{ g}\). Molar mass of A (\(M_A\)) = \(140 \text{ g/mol}\). Molar mass of water (\(M_W\)) = \(18 \text{ g/mol}\). Number of moles of A…