Question

0.316 g of an organic compound, after heating with fuming nitric acid and barium nitrate crystals in a sealed tube gave 0.466 g of the precipitate of barium sulphate. Determine the percentage of sulphur in the compound. 

(Atomic masses : Ba = 137, S = 32, O = 16, C = 12, H = 1). 

Answer 1

Mass of the substance taken = 0.316 g 

Mass of BaSO₄ formed = 0.466 g 

Molecular mass of BaSO₄ = 137 + 32 + 64 = 233 

Then, mass of S in 0.466 g of BaSO₄

= 0.466 x 32 / 233 g

Percentage of S in compound 

= 0.466 x 32 x 100 / 233 x 0. 316

= 20.25