In the Carius method for the estimation of sulphur, an organic compound containing 8 % sulphur by mass produced 699 mg of barium sulphate. The mass of the organic compound taken for the estimation is _______ mg . (Given molar mass in g mol ⁻¹ of Ba : 137, S : 32, O : 16 )

Step-by-step solution

Molar mass of BaSO ₄ = 137 + 32 + 4 16 = 233 g mol ⁻¹ Millimoles of BaSO ₄ formed = 699 233 = 3 mmol Since one mole of BaSO ₄ contains one mole of sulphur, millimoles of sulphur = 3 mmol Mass of sulphur in the compound = 3 32 = 96 mg Let the mass of the organic compound taken be W mg . Percentage of sulphur = Mass of sulphur W 100 8 = 96 W 100 W = 9600 8 = 1200 mg Answer: 1200