The eq.wt. of `Fe_(2)(SO_(4))_(3)`, the salt to be used as an oxidant in an acid solution is

Options

A. `(mol.wt.)//1`
B. `(mol.wt.)//2`
C. `(mol.wt.)//3`
D. `(mol.wt.)//5`

Explanation

To find the equivalent weight of \( \text{Fe}_2(\text{SO}_4)_3 \), we will follow these steps:

### Step 1: Determine the molar mass of \( \text{Fe}_2(\text{SO}_4)_3 \)

The molar mass can be calculated by adding the atomic masses of all the elements in the compound:

- Iron (Fe): 55.85 g/mol
- Sulfur (S): 32.07 g/mol
- Oxygen (O): 16.00 g/mol

The formula \( \text{Fe}_2(\text{SO}_4)_3 \) contains:
- 2 Fe atoms
- 3 S atoms
- 12 O atoms (4 O in each sulfate, 3 sulfates)

Calculating the molar mass:
\[ \text{Molar mass} = (2 \times 55.85) + (3 \times 32.07) + (12 \times 16.00) \]
\[ = 111.70 + 96.21 + 192.00 = 399.91 \text{ g/mol} \]

### Step 2: Determine the change in oxidation state

In the reaction, \( \text{Fe}_2(\text{SO}_4)_3 \) is reduced to \( \text{Fe}^{2+} \). The oxidation state of iron changes from +3 in \( \text{Fe}_2(\text{SO}_4)_3 \) to +2 in \( \text{Fe}^{2+} \).

### Step 3: Calculate the number of electrons gained

Each iron atom gains 1 electron (from +3 to +2). Since there are 2 iron atoms in \( \text{Fe}_2(\text{SO}_4)_3 \), the total number of electrons gained is:
\[ \text{Total electrons gained} = 2 \text{ electrons} \]

### Step 4: Determine the equivalent weight

The equivalent weight is calculated using the formula:
\[ \text{Equivalent weight} = \frac{\text{Molar mass}}{\text{n}} \]
where \( n \) is the number of electrons gained (which is the balance factor).

Substituting the values:
\[ \text{Equivalent weight} = \frac{399.91 \text{ g/mol}}{2} = 199.955 \text{ g/equiv} \]

### Final Answer

The equivalent weight of \( \text{Fe}_2(\text{SO}_4)_3 \) is approximately **199.96 g/equiv**.

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