Question

$0.245 \text{ gm}$ of an unknown organic compound gave $0.5453 \text{ gm}$ of $\text{AgCl}$ through Carious method. Calculate $%$ of $\text{Cl}$ in unknown compound.

• A. $55.06$
• B. $45.12$
• C. $35.50$
• D. $25.25$

Hint:

Carious method calculates the percentage of halogens by converting the halogen present in the organic sample into a silver halide ($\text{AgX}$). The relationship relies on the mole ratio of the halogen to the silver halide (1:1).

Answer 1

The Correct Option is A

To find the percentage of \(\text{Cl}\) in the unknown organic compound, we need to first understand the Carious method. The Carious method involves converting the chlorine in an organic compound into silver chloride (\(\text{AgCl}\)), which can then be weighed.

We start by noting the given data: 

• Mass of the unknown organic compound = \(0.245 \, \text{gm}\)
• Mass of \(\text{AgCl}\) formed = \(0.5453 \, \text{gm}\)

The reaction involved is as follows:

\(\text{Cl} + \text{Ag}^+ \rightarrow \text{AgCl}\)

In this reaction, 1 mol of chlorine (Cl) reacts to form 1 mol of silver chloride (AgCl). Therefore, the moles of chlorine are equivalent to the moles of AgCl formed.

Now, we calculate the moles of \(\text{AgCl}\) produced using the formula:

\(\text{Moles of AgCl} = \frac{\text{Mass of AgCl}}{\text{Molar mass of AgCl}}\)

The molar mass of \(\text{AgCl}\) is:

• Silver (Ag) = 107.87 g/mol
• Chlorine (Cl) = 35.45 g/mol

Thus, the molar mass of \(\text{AgCl}\) = \(107.87 + 35.45 = 143.32 \, \text{g/mol}\)

Calculating the moles of \(\text{AgCl}\):

\(\text{Moles of AgCl} = \frac{0.5453}{143.32} \approx 0.0038 \, \text{mol}\)

These are also the moles of chlorine, as explained earlier. The mass of chlorine, therefore, is:

\(\text{Mass of Cl} = \text{moles of Cl} \times \text{Molar mass of Cl} = 0.0038 \times 35.45 \approx 0.1347 \, \text{gm}\)

Finally, we calculate the percentage of \(\text{Cl}\) in the compound:

\(\text{Percentage of Cl} = \left(\frac{\text{Mass of Cl}}{\text{Mass of compound}}\right) \times 100 = \left(\frac{0.1347}{0.245}\right) \times 100 \approx 55.00\%\)

The correct answer is approximately 55.06%, which matches the given options. Therefore, the correct choice is:

• 55.06%