Which one is o, p-directiong group for electrophliic substitution reaction ?

Options

A. `-overset(O)overset(||)C-OH`
B. `-overset(O)overset(||)C-NH_(2)`
C.
D. `-NO_(2)`

Answer

To determine which group is ortho-para directing for electrophilic substitution reactions in aromatic compounds, we need to analyze the nature of the substituents on the benzene ring. Here’s a step-by-step solution:

### Step 1: Understand Electrophilic Substitution
Electrophilic substitution reactions occur on aromatic rings, such as benzene, where an electrophile replaces a hydrogen atom. The positions where the electrophile can attack are the ortho (adjacent) and para (opposite) positions relative to the substituent.

### Step 2: Identify Activating and Deactivating Groups
- **Activating Groups**: These groups increase the electron density on the aromatic ring, particularly at the ortho and para positions. They usually have lone pairs of electrons that can be donated into the ring, or they can have a positive inductive effect (+I).
- **Deactivating Groups**: These groups decrease the electron density on the ring and make electrophilic substitution less favorable. They typically withdraw electron density through resonance or inductive effects.

### Step 3: List Common Activating Groups
Common ortho-para directing activating groups include:
- -NH2 (amino group)
- -OH (hydroxyl group)
- -OCH3 (methoxy group)
- -R (alkyl groups like -CH3)

### Step 4: Analyze the Given Options
In the question, we need to evaluate the groups provided (not listed here, but typically options like -NO2, -CHO, -NH2, etc.) to identify which one is ortho-para directing:
- **Example of Deactivators**: -NO2 (nitro), -CHO (aldehyde), -CN (cyano) are all deactivating groups and will direct electrophilic substitution to the meta position instead of ortho or para.
- **Example of Activators**: -NH2 (amino) is an activating group and will direct electrophilic substitution to the ortho and para positions.

### Step 5: Conclusion
Based on the analysis, the group that is ortho-para directing for electrophilic substitution is the one that is an activating group. If we assume option C is an activating group (like -NH2), then it is the correct answer.

### Final Answer
The ortho-para directing group for electrophilic substitution reaction is **option C** (assuming it is an activating group like -NH2).

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