Which among the following will not act as a reducing agent?

Options

A. `KNO_2`
B. `KI`
C. `NaNO_3`
D. `H_2S`

Answer

To determine which among the given options will not act as a reducing agent, we need to understand the concept of reducing agents and their properties.

### Step-by-Step Solution:

1. **Understanding Reducing Agents**: A reducing agent is a substance that loses electrons and gets oxidized in a chemical reaction. This means that for a substance to act as a reducing agent, it must be capable of being oxidized itself.

2. **Analyzing the Options**:
- **Option 1: Potassium Nitrate (KNO3)**: This compound contains nitrate ions (NO3-), which are generally stable and do not easily lose electrons. Therefore, KNO3 is unlikely to act as a reducing agent.

- **Option 2: Potassium Iodide (KI)**: In this compound, iodine (I) has a -1 oxidation state. It can lose an electron to become elemental iodine (I2), which means it can act as a reducing agent.

- **Option 3: Sodium Nitrate (NaNO3)**: Similar to potassium nitrate, sodium nitrate contains nitrate ions (NO3-). The nitrogen in nitrate is already in a high oxidation state (+5), and it cannot be oxidized further. Thus, NaNO3 cannot act as a reducing agent.

- **Option 4: NO2- (Nitrite Ion)**: The nitrite ion can be oxidized to nitrate (NO3-), which means it can act as a reducing agent.

3. **Conclusion**: Among the options provided, both Potassium Nitrate (KNO3) and Sodium Nitrate (NaNO3) do not act as reducing agents. However, since the question asks for the one that will not act as a reducing agent, the best answer is **Sodium Nitrate (NaNO3)**, as it is already in its highest oxidation state and cannot be oxidized further.

### Final Answer:
**Sodium Nitrate (NaNO3)** will not act as a reducing agent.

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