Question

Sodium extract of organic compound of 0.1 g is treated with chlorine water and \( \text{CCl}_4 \) which dissolves in organic solvent to produce a violet colour. Upon treatment with \( \text{AgNO}_3 \), a yellow ppt. of 0.12 g is produced. Calculate the percentage of halide in the organic compound.

Hint:

When calculating the percentage of halide, use the molar mass of the halide and the mass of the precipitate to determine the moles of halide present.

Answer 1

Correct Answer: 65

To solve the problem, we first need to determine the mass of halide in the organic compound. The reaction with \( \text{AgNO}_3 \) producing 0.12 g of a yellow precipitate indicates the formation of silver halide, likely \( \text{AgI} \) due to its distinctive yellow color. We will calculate the mass of iodine in the precipitate and then determine the percentage of iodine in the original organic compound.

1. **Molar Mass Calculations**: The molar mass of \( \text{AgI} \) (Silver iodide) is approximately 234.77 g/mol (Ag: 107.87, I: 126.90).

2. **Calculate Iodine Mass in Precipitate**: Use stoichiometry to find the mass of iodine in 0.12 g of \( \text{AgI} \).

\(\text{Mass of Iodine} = \frac{\text{Mass of AgI}}{\text{Molar Mass of AgI}} \times \text{Molar Mass of I}\)

\(\text{Mass of Iodine} = \frac{0.12\ \text{g}}{234.77\ \text{g/mol}} \times 126.90\ \text{g/mol}\)

\(\text{Mass of Iodine} \approx 0.0648\ \text{g}\)

3. **Percentage of Iodine in Organic Compound**: Calculate the percentage of iodine in the original 0.1 g sample.

\(\text{Percentage of Iodine} = \left(\frac{\text{Mass of Iodine}}{\text{Mass of Organic Compound}}\right) \times 100\)

\(\text{Percentage of Iodine} = \left(\frac{0.0648\ \text{g}}{0.1\ \text{g}}\right) \times 100\)

\(\text{Percentage of Iodine} = 64.8\%\)

4. **Verification**: Confirm the calculated percentage fits within the given range.\

The computed 64.8% is indeed within the expected range of 65, verifying its correctness.