Statement I: Aniline on reaction with ` NaNO_2 HCl` at `0^@C` followed by coupling with `beta`-naphthol gives a dark blue coloured precipitate.
Statement II: The colour of the compound formed in the reaction of aniline with `NaNO_2//HCl` at ` 0^@C` followed by coupling with `beta`-naphthol is due to extended conjugation.

Options

A. Statement (I) is true : Statement (II) is true : Statement (II) is the correct esplanation of Statement (I)
B. Statement (I) is true : Statement (II) is true , Statement (II) is not the correct exphanation fo sTatement (I)
C. Statement I is True, Statament II is false
D. Statement (I) is false , Statement (II) is true .

Explanation

To analyze the given statements, let's break down the reactions and concepts involved step by step.

### Step 1: Understanding the Reaction of Aniline with NaNO2 and HCl
Aniline (C6H5NH2) reacts with sodium nitrite (NaNO2) in the presence of hydrochloric acid (HCl) at low temperatures (0°C to 5°C). This reaction leads to the formation of benzene diazonium chloride (C6H5N2Cl).

**Hint:** Remember that diazonium salts are formed from primary amines in acidic conditions.

### Step 2: Formation of Benzene Diazonium Chloride
The reaction can be summarized as follows:
\[ \text{C6H5NH2} + \text{NaNO2} + \text{HCl} \rightarrow \text{C6H5N2Cl} + \text{NaCl} + \text{H2O} \]

Here, aniline is converted to benzene diazonium chloride, which is a key intermediate in azo coupling reactions.

**Hint:** Focus on the role of sodium nitrite and HCl in converting aniline to a diazonium compound.

### Step 3: Coupling with Beta-Naphthol
Next, the benzene diazonium chloride reacts with beta-naphthol (C10H7OH). This reaction occurs at low temperatures and results in the formation of an azo dye.

The coupling reaction can be represented as:
\[ \text{C6H5N2Cl} + \text{C10H7OH} \rightarrow \text{C6H5N=N-C10H7OH} + \text{HCl} \]

This forms an azo compound, which typically has a vivid color due to the presence of the azo (-N=N-) linkage.

**Hint:** Azo coupling reactions often produce colored compounds due to the extended conjugation of π-electrons.

### Step 4: Color of the Azo Compound
The resulting azo compound from the coupling of benzene diazonium chloride with beta-naphthol is known to be orange-red in color, not dark blue as stated in Statement I. The color arises from the extended conjugation in the molecule, which allows for the absorption of visible light.

**Hint:** Recall that the color of organic compounds can often be attributed to their conjugated systems.

### Step 5: Evaluating the Statements
- **Statement I:** Aniline on reaction with NaNO2 and HCl at 0°C followed by coupling with beta-naphthol gives a dark blue colored precipitate.
- This statement is **incorrect** because the product is orange-red, not dark blue.

- **Statement II:** The color of the compound formed in the reaction is due to extended conjugation.
- This statement is **correct** as the extended conjugation in the azo compound contributes to its color.

### Conclusion
Thus, the correct evaluation of the statements is:
- Statement I is false.
- Statement II is true.

The final answer is that Statement I is incorrect while Statement II is correct.

**Final Answer:** Statement I is false, Statement II is true.