Question

In ‘S’ estimation, \(0.314\,\text{g}\) of an organic compound gave \(0.4813\,\text{g}\) of barium sulphate. What is the percentage (%) of sulphur in the organic compound? (Report to nearest integer)

Hint:

For sulphur estimation using \(\text{BaSO}_4\): always multiply the mass of \(\text{BaSO}_4\) by \(\dfrac{32}{233}\) to get mass of sulphur.

Answer 1

Correct Answer: 21

Concept:
In sulphur estimation (Carius method), sulphur present in the compound is converted into \(\text{BaSO}_4\).

Molar mass of \(\text{BaSO}_4 = 233\,\text{g/mol}\)
Atomic mass of sulphur \(= 32\,\text{g/mol}\)

Step 1: Calculate Mass of Sulphur in \(\text{BaSO}_4\)
\[ \text{Mass of S} = \frac{32}{233} \times 0.4813 \] \[ \text{Mass of S} \approx 0.066\,\text{g} \]
Step 2: Calculate Percentage of Sulphur
Mass of organic compound \(= 0.314\,\text{g}\) \[ %\text{ of S} = \frac{0.066}{0.314} \times 100 \] \[ %\text{ of S} \approx 21% \] \[ \boxed{%\text{ of S} = 21%} \]