Phenol, when it first react with concentrated sulphuric acid and with concentrated nitric acid, gives

Options

A. o-nitrophenol
B. p-nitrophenol
C. nitrobenzenes
D. 2,4,6-rinitrobenzene

Answer

To solve the question regarding the reaction of phenol with concentrated sulfuric acid followed by concentrated nitric acid, we can break down the steps as follows:

### Step-by-Step Solution:

1. **Identify the Reactant**:
- The reactant is phenol (C6H5OH), which consists of a benzene ring with a hydroxyl (OH) group attached.

2. **Reaction with Concentrated Sulfuric Acid**:
- When phenol reacts with concentrated sulfuric acid (H2SO4), it undergoes sulfonation. The concentrated sulfuric acid generates the electrophile SO3H (sulfonyl group).
- The OH group on phenol is an electron-donating group, which increases the electron density at the ortho and para positions of the benzene ring.
- Due to steric hindrance, the electrophile SO3H will predominantly attack the para position relative to the OH group.
- The product formed from this reaction is para-hydroxyl-benzenesulfonic acid (C6H4(OH)(SO3H) at the para position).

3. **Reaction with Concentrated Nitric Acid**:
- Next, the product from the first reaction is treated with concentrated nitric acid (HNO3). This reaction is a nitration process.
- The concentrated nitric acid generates the electrophile NO2+ (nitronium ion).
- The OH group is still the dominating group, and it increases the electron density at the ortho and para positions.
- The NO2+ ion can replace the SO3H group at the para position because it is a strong electrophile and can easily substitute for the sulfonyl group.
- The final product will have two nitro groups: one at the para position and one at the ortho position relative to the OH group.
- The resulting compound is 2,4,6-trinitrophenol, commonly known as picric acid.

4. **Conclusion**:
- Therefore, the final product after the two reactions is **2,4,6-trinitrophenol (picric acid)**.

### Final Answer:
The product formed when phenol first reacts with concentrated sulfuric acid and then with concentrated nitric acid is **picric acid (2,4,6-trinitrophenol)**.