The equivalent mass of oxidising agent in the following reaction is
`SO_(2)+2H_(2)Srarr3S+2H_(2)O`

Options

A. `32`
B. `64`
C. `16`
D. `8`

Explanation

To find the equivalent mass of the oxidizing agent in the reaction \( SO_2 + 2H_2S \rightarrow 3S + 2H_2O \), we will follow these steps:

### Step 1: Identify the Oxidation States
First, we need to determine the oxidation states of sulfur in the reactants and products.

- In \( SO_2 \):
- Let the oxidation state of sulfur be \( x \).
- The oxidation state of oxygen is \(-2\).
- The equation for sulfur in \( SO_2 \) is:
\[ x + 2(-2) = 0 \implies x - 4 = 0 \implies x = +4 \]
- Therefore, the oxidation state of sulfur in \( SO_2 \) is +4.

- In \( H_2S \):
- The oxidation state of sulfur is \(-2\) (since hydrogen is +1).

- In the product \( S \):
- The oxidation state of sulfur is 0 (elemental form).

### Step 2: Determine Changes in Oxidation States
Now, we analyze the changes in oxidation states:

- From \( SO_2 \) (oxidation state +4) to \( S \) (oxidation state 0):
- This is a reduction process, where sulfur is gaining electrons.

- From \( H_2S \) (oxidation state -2) to \( S \) (oxidation state 0):
- This is an oxidation process, where sulfur is losing electrons.

### Step 3: Identify the Oxidizing Agent
Since \( SO_2 \) is being reduced (gaining electrons), it acts as the oxidizing agent in this reaction.

### Step 4: Calculate the Number of Electrons Transferred
In the reaction:
- Each \( SO_2 \) gains 4 electrons (from +4 to 0).
- Each \( H_2S \) loses 2 electrons (from -2 to 0).

### Step 5: Determine the Equivalent Mass
The equivalent mass of an oxidizing agent can be calculated using the formula:
\[ \text{Equivalent mass} = \frac{\text{Molecular weight}}{\text{Number of electrons transferred}} \]

- The molecular weight of \( SO_2 \) is:
\[ \text{Molar mass of } SO_2 = 32 \, (\text{for S}) + 2 \times 16 \, (\text{for O}) = 64 \, \text{g/mol} \]

- The number of electrons transferred by one mole of \( SO_2 \) is 4.

Thus, the equivalent mass of \( SO_2 \) is:
\[ \text{Equivalent mass} = \frac{64 \, \text{g/mol}}{4} = 16 \, \text{g/equiv} \]

### Final Answer
The equivalent mass of the oxidizing agent \( SO_2 \) is **16 g/equiv**.

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