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

Step 1: Molar mass of silver chloride.
The molar mass of \( \text{AgCl} \) is: \[ M_{\text{AgCl}} = 143.5 \, \text{g/mol} \] Step 2: Moles of \( \text{AgCl} \) formed.
The mass of \( \text{AgCl} \) formed is 0.12 g. To find the moles of \( \text{AgCl} \), use the formula: \[ \text{moles of } \text{AgCl} = \frac{\text{mass}}{\text{molar mass}} = \frac{0.12}{143.5} = 8.36 \times 10^{-4} \, \text{mol} \] Step 3: Moles of halide in the compound.
Since the moles of \( \text{AgCl} \) correspond to the moles of halide in the organic compound, the moles of halide = \( 8.36 \times 10^{-4} \) mol. Step 4: Calculate the percentage of halide.
The number of moles of halide corresponds to \( 8.36 \times 10^{-4} \) mol in a 0.1 g sample of the compound. The mass of halide in the compound is: \[ \text{Mass of halide} = 8.36 \times 10^{-4} \, \text{mol} \times 143.5 \, \text{g/mol} = 0.12 \, \text{g} \] Now, the percentage of halide in the organic compound is: \[ \text{Percentage of halide} = \frac{0.12 \, \text{g}}{0.1 \, \text{g}} \times 100 = 65% \] Final Answer: \[ \boxed{65%} \]