Question

In sulphur estimation, $0471 \,g$ of an organic compound gave $14439 \,g$ of barium sulphate The percentage of sulphur in the compound is ___(Nearest Integer) (Grven: Atomic mass Ba: $137 \,u , S : 32\, u , O : 16 \,u$ )

Answer 1

Correct Answer: 42

1. Molar mass of BaSO$_4$: 
\[ M = 137 + 32 + 64 = 233 \, \text{g/mol}. \] 
2. Mass of sulphur in BaSO$_4$: 
\[ \text{Mass of S} = \frac{32}{233} \times \text{mass of BaSO$_4$}. \] 
3. Substituting the given mass of BaSO$_4$: 
\[ \text{Mass of S} = \frac{32}{233} \times 1.4439 = 0.1984 \, \text{g}. \] 
4. Percentage of sulphur: 
\[ \% \text{S} = \frac{\text{Mass of S}}{\text{Mass of compound}} \times 100 = \frac{0.1984}{0.471} \times 100 = 42.10 \%. \] 
Thus, the percentage of sulphur is \(42\%\). In sulphur estimation, the amount of sulphur is directly calculated from the mass of BaSO$_4$ formed, using stoichiometric relations.