Estimation of halogens:
Carisu Method: A known mass of compound is heated with conc. `HNO_(3)` in the presence of `AgNO_(3)` contained in a hard glass tube known as carius tube in a furnce. C and H are oxidised to `CO_(2)` and `H_(2)O` . The halogen forms the corresponding AgX. It is filtered , dried , and weighed.
Estimation of sulphur: A known mass of compound is heated with fuming `HNO_(3)` or sodium peroxide `(Na_(2)O_(2))` in the presence of `BaCl_(2)` solution in Carius tube. Sulphur is oxidised to `H_(2)SO_(4)` and precipitated as `BaSO_(4)` . It is filerted, dried and weighed.
0.32 gm of an organic substance when treated by Carius method gave 0.466 gm of `BaSO_(4)` . Calculate the percentage of sulphur in the compound (Ba=137)

Options

A. `10.0`
B. `34.0`
C. `20.0`
D. `30.0`

Answer

To calculate the percentage of sulfur in the organic compound using the data provided, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Known Values:**
- Mass of the organic compound (m_compound) = 0.32 g
- Mass of BaSO₄ obtained (m_BaSO₄) = 0.466 g
- Atomic mass of sulfur (S) = 32 g/mol
- Atomic mass of barium (Ba) = 137 g/mol
- Atomic mass of oxygen (O) = 16 g/mol

2. **Calculate the Molar Mass of BaSO₄:**
\[ \text{Molar mass of BaSO}_4 = \text{Ba} + \text{S} + 4 \times \text{O} \]
\[ = 137 + 32 + (4 \times 16) = 137 + 32 + 64 = 233 \text{ g/mol} \]

3. **Use the Formula for Percentage of Sulfur:**
The formula for calculating the percentage of sulfur in the compound is:
\[ \text{Percentage of S} = \left( \frac{\text{Atomic mass of S}}{\text{Molar mass of BaSO}_4} \right) \times \left( \frac{\text{Mass of BaSO}_4}{\text{Mass of compound}} \right) \times 100 \]

4. **Substitute the Values into the Formula:**
\[ \text{Percentage of S} = \left( \frac{32}{233} \right) \times \left( \frac{0.466}{0.32} \right) \times 100 \]

5. **Calculate Each Part:**
- Calculate \( \frac{32}{233} \):
\[ \frac{32}{233} \approx 0.137 \]
- Calculate \( \frac{0.466}{0.32} \):
\[ \frac{0.466}{0.32} \approx 1.45625 \]
- Now multiply these results and then by 100:
\[ \text{Percentage of S} \approx 0.137 \times 1.45625 \times 100 \approx 20.00\% \]

### Final Answer:
The percentage of sulfur in the compound is approximately **20%**.