Cartain materials such as turpentine oil, unsaturated organic compound, phosophorus, metals such as `Zn`, and `Pb`, etc., can absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to `H_(2)O_(2)`. This is called autoxidation. Intermolecular redox reactions are those in which one molecule is oxidised and the other is reduced. Intramolecular redox reactions are those in which oen atom of a molecule is oxidised and the other atom is reduced.
Which of the following reactions is`//`are none of the reactions mentioned in the question?

Options

A. `Ag(NH_(3))^(o+)overset(2H^(o+))rarrAg^(o+)+NH_(4)^(o+)`
B. `Cr_(2)O_(7)^(2-)+2overset(ө)OHrarr2CrO_(4)^(2-)+H_(2)O`
C. `NH_(4)^(o+)rarrNH_(3)`
D. `2NO_(2)rarrN_(2)O_(4)`

Explanation

To solve the question regarding which reactions are not classified as auto-oxidation, intermolecular redox reactions, or intramolecular redox reactions, we will analyze each reaction step by step.

### Step 1: Understand the Definitions
- **Auto-oxidation**: A process where a substance absorbs oxygen from the air in the presence of water, leading to the formation of hydrogen peroxide (H₂O₂).
- **Intermolecular redox reactions**: Reactions where one molecule is oxidized while another molecule is reduced.
- **Intramolecular redox reactions**: Reactions where one atom of a molecule is oxidized and another atom of the same molecule is reduced.

### Step 2: Analyze Each Reaction
1. **Reaction 1: Ag + N₂ → AgN**
- Oxidation state of Ag is +1 and N is -3 in both reactants and products.
- No change in oxidation states indicates it is not a redox reaction.

2. **Reaction 2: CrO₄²⁻ + OH⁻ → Cr(OH)₆²⁻**
- The oxidation state of Cr is +6 in both reactants and products.
- No change in oxidation states indicates it is not a redox reaction.

3. **Reaction 3: N₂ + H₂ → NH₃**
- The oxidation state of N changes from 0 in N₂ to -3 in NH₃, while H changes from 0 to +1.
- This indicates a redox reaction, as there is a change in oxidation states.

4. **Reaction 4: 2NO₂ → N₂O₄**
- The oxidation state of N remains +4 in both reactants and products.
- No change in oxidation states indicates it is not a redox reaction.

### Step 3: Conclusion
Based on the analysis:
- Reactions 1, 2, and 4 do not involve any changes in oxidation states and are therefore not classified as redox reactions.
- Reaction 3 is a redox reaction.

### Final Answer
The reactions that are none of the types mentioned in the question are:
- Reaction 1: Ag + N₂ → AgN
- Reaction 2: CrO₄²⁻ + OH⁻ → Cr(OH)₆²⁻
- Reaction 4: 2NO₂ → N₂O₄

Thus, the correct options are A, B, and D.