In Zeisel's method for the detrmination of methoxyl groups, a sample of `2.68` gm of a compound (A) gave `14.08` gm of AgI. If the molecular weight of compound (A) is 134, the number of `(--OH_))` group(s) in the compound (A) is:

Options

A. 1
B. 2
C. 3
D. 4

Explanation

To determine the number of hydroxyl groups (–OH) in compound (A) using Zeisel's method, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Mass of compound (A) = 2.68 g
- Mass of AgI formed = 14.08 g
- Molecular weight of compound (A) = 134 g/mol

2. **Calculate the Moles of Compound (A):**
\[ \text{Moles of compound (A)} = \frac{\text{mass}}{\text{molecular weight}} = \frac{2.68 \, \text{g}}{134 \, \text{g/mol}} = 0.02 \, \text{mol} \]

3. **Determine the Molar Mass of Silver Iodide (AgI):**
- The molar mass of AgI = Atomic mass of Ag (107.87 g/mol) + Atomic mass of I (126.90 g/mol) = 234.77 g/mol

4. **Calculate the Moles of Silver Iodide (AgI):**
\[ \text{Moles of AgI} = \frac{\text{mass of AgI}}{\text{molar mass of AgI}} = \frac{14.08 \, \text{g}}{234.77 \, \text{g/mol}} \approx 0.06 \, \text{mol} \]

5. **Relate Moles of Compound (A) to Moles of AgI:**
- According to Zeisel's method, the moles of AgI formed are directly related to the number of methoxy groups in compound (A).
- If \( x \) is the number of methoxy groups, then:
\[ \text{Moles of AgI} = x \times \text{Moles of compound (A)} \]
- Thus, we can write:
\[ 0.06 \, \text{mol} = x \times 0.02 \, \text{mol} \]

6. **Solve for \( x \):**
\[ x = \frac{0.06}{0.02} = 3 \]

7. **Conclusion:**
- The number of hydroxyl groups (–OH) in compound (A) is equal to the number of methoxy groups, which is **3**.

### Final Answer:
The number of (–OH) groups in compound (A) is **3**.

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