Which of the following is not oxidised by `MnO_(2)` ?

Options

A. `F^(-)`
B. `Cl^(-)`
C. `Br^(-)`
D. `I^(-)`

Answer

To determine which of the following halogens is not oxidized by MnO₂, we will analyze each option systematically.

### Step 1: Understand the Oxidizing Agent
MnO₂ (Manganese Dioxide) is a strong oxidizing agent. It has the ability to accept electrons from other substances, leading to their oxidation.

### Step 2: Analyze the Halogens
The options provided are likely to be halogens, which include Fluorine (F), Chlorine (Cl), Bromine (Br), and Iodine (I). We will examine each halogen to see if it can be oxidized by MnO₂.

### Step 3: Examine Fluorine (F)
- Fluorine has the electron configuration of [He] 2s² 2p⁵, meaning it has 7 electrons in its outer shell.
- Fluorine is highly electronegative and prefers to gain an electron rather than lose electrons.
- Due to its small size and high electronegativity, it is very difficult for fluorine to lose electrons, making it resistant to oxidation by MnO₂.

### Step 4: Examine Chlorine (Cl)
- Chlorine has 7 electrons in its outer shell as well, but it is larger than fluorine.
- Chlorine can lose an electron more easily compared to fluorine, and thus can be oxidized by MnO₂.

### Step 5: Examine Bromine (Br)
- Bromine is larger than chlorine and can also lose electrons more readily.
- Therefore, bromine can be oxidized by MnO₂.

### Step 6: Examine Iodine (I)
- Iodine is the largest among the halogens listed and can easily lose electrons.
- Hence, iodine can also be oxidized by MnO₂.

### Conclusion
From the analysis, we conclude that **Fluorine (F)** is not oxidized by MnO₂ due to its high electronegativity and difficulty in losing electrons. Therefore, the correct answer is:

**Option A: Fluorine (F)**

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