Assertion : The presence of nitro group facilitates nucleophilic substiution reactions in aryl halides. Reason : The intermediate carbanion is stabilised due to the presence of nitro group.

Options

A. a. if both Assertion and Reason are true and reason is the correct explanation of the assertion.
B. b. if both assertion and reason are true but reason is not the correct expalanation of the assertion
C. c. if assertion is true, reason is false
D. d. both assertion and reason are false statements.

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that "The presence of nitro group facilitates nucleophilic substitution reactions in aryl halides."
- Aryl halides are compounds where a halogen atom is bonded to an aromatic ring.
- The nitro group (-NO2) is an electron-withdrawing group that increases the electrophilicity of the aromatic ring. This means that it makes the ring more susceptible to nucleophilic attack.

**Hint:** Consider how electron-withdrawing groups affect the reactivity of aromatic compounds.

### Step 2: Understand the Reason
The reason states that "The intermediate carbanion is stabilized due to the presence of nitro group."
- In nucleophilic aromatic substitution (SNAr), a nucleophile attacks the aromatic ring, forming a negatively charged intermediate (carbanion).
- The nitro group can stabilize this carbanion through resonance. When the carbanion forms, the negative charge can be delocalized onto the nitro group, which stabilizes the intermediate.

**Hint:** Think about how resonance structures can distribute charge and stabilize intermediates.

### Step 3: Analyze the Relationship
Now, we need to determine if the reason correctly explains the assertion.
- Since the nitro group does facilitate nucleophilic substitution by stabilizing the carbanion intermediate, the reason does indeed provide a correct explanation for the assertion.

**Hint:** Reflect on whether the stabilization of the intermediate is crucial for the reaction to proceed.

### Conclusion
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

### Final Answer
The correct option is: **A** - Both assertion and reason are true, and reason is the correct explanation of the assertion.