Assertion: `N_(2)H_(4)` cannot reduce `S_(2)O_(3)^(2-)`
Reason : `S_(2)O_(3)^(2-)` is converted to `S_(4)O_(6)^(2-)`

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false
D. If the assertion and reason both are false.

Explanation

To analyze the assertion and reason provided in the question, we will break down the concepts involved and provide a step-by-step solution.

### Step 1: Understand the Assertion
The assertion states that \(N_2H_4\) (hydrazine) cannot reduce \(S_2O_3^{2-}\) (thiosulfate ion).

**Hint:** Recall the properties of hydrazine and its reducing capabilities.

### Step 2: Analyze the Reducing Agent
Hydrazine (\(N_2H_4\)) is known to be a reducing agent, but its effectiveness depends on the species it is reacting with.

**Hint:** Consider what makes a good reducing agent and the nature of the thiosulfate ion.

### Step 3: Understand the Reason
The reason states that \(S_2O_3^{2-}\) is converted to \(S_4O_6^{2-}\) (tetrathionate ion). This transformation typically occurs in reactions involving oxidation.

**Hint:** Think about the oxidation states of sulfur in both thiosulfate and tetrathionate.

### Step 4: Evaluate the Reaction
When \(S_2O_3^{2-}\) is oxidized, it can form \(S_4O_6^{2-}\). However, for \(N_2H_4\) to reduce \(S_2O_3^{2-}\), it would need to provide electrons, which it cannot do effectively in this case.

**Hint:** Consider the electron transfer process and the stability of the products formed.

### Step 5: Conclusion on Assertion and Reason
Both the assertion and the reason are true:
- The assertion is correct because \(N_2H_4\) cannot reduce \(S_2O_3^{2-}\).
- The reason is also correct as \(S_2O_3^{2-}\) can be converted to \(S_4O_6^{2-}\) through oxidation.

However, the reason does not adequately explain the assertion, as it does not address why \(N_2H_4\) cannot act as a reducing agent in this case.

**Final Conclusion:** The correct option would be that both assertion and reason are true, but the reason is not the correct explanation for the assertion.

### Summary
- Assertion: True
- Reason: True
- Explanation: The reason does not correctly explain the assertion.