Question

An organic compound weighs $0.316$ g 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: $Ba=137,S=32,O=16,C=12,H=1$).

• A. $21$%
• B. $20.25$%
• C. $29$%
• D. $24$%

Answer 1

The correct option is B $20.25$%

Mass of the substance taken = $0.316g$

Mass of $BaS{O}_4$ formed =$0.466g$

From stoichiometry,

molecular mass of the $BaS{O}_4$ $=137+32+64=233$

Mass of $S$ in $0.466g$ of $BaS{O}_4$=$\frac{0.466\times 32}{233}g$

Percentage of $S$ in the compound=$\frac{0.466\times 32}{233}\times \frac{100}{0.316}=20.25$