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Solutions

Question
CBSEENCH12005817

An aqueous solution of 2 percent non-volatile solute exerts a pressure of 0.096 atm at the boiling poine of the solvent. What is the molecular mass of the solute ?

Solution

  At the boiling point of pure solvent the vapour preesure is 1 atmp0 =1 Atmp =0.096p0-pp0 =0.0042% solution means 2g solute in 100g solution,sowB =2gwA =98gMA =18g/molwe know that MB =wBMAwAp0-pp0 =2 x1898 x 0.004   =45.5g/mol