Assertion(A): Borazole is aromatic is nature.
Reason(R): Nitrogen contributes `pi` - electrons to the system.

Options

A. if both (A) and (R) are correct and (R) is the correct explanation of (A)
B. if both (A) and (R) are correct and (R) is not the correct explanation of (A)
C. If (A) is correct but (R) is incorrect
D. If (A) is incorrect but (R) is correct

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts step by step.

### Step 1: Understanding Borazole
Borazole, also known as borazine, has the molecular formula B₃N₃H₆. It consists of alternating boron and nitrogen atoms in a six-membered ring structure, similar to benzene.

**Hint:** Recall the structure of borazine and its components (boron and nitrogen).

### Step 2: Drawing the Structure
The structure of borazole can be depicted as follows:
- Three boron (B) atoms and three nitrogen (N) atoms are arranged in a cyclic manner.
- Each boron atom is bonded to a nitrogen atom, and vice versa, with hydrogen atoms completing the valency.

**Hint:** Visualize the alternating pattern of boron and nitrogen atoms in the ring.

### Step 3: Identifying Electron Contribution
In borazole, nitrogen atoms have lone pairs of electrons. These lone pairs can be donated to the electron-deficient boron atoms, forming bonds. This donation of electrons contributes to the delocalization of π-electrons in the ring.

**Hint:** Consider how lone pairs can participate in bonding and contribute to aromaticity.

### Step 4: Checking for Aromaticity
According to Huckel's rule, a compound is aromatic if it has (4n + 2) π-electrons, where n is a non-negative integer. In borazole:
- Each nitrogen contributes one π-electron from its lone pair.
- There are three nitrogen atoms contributing a total of 3 π-electrons.
- The boron atoms do not contribute π-electrons but help stabilize the structure.

Thus, borazole has a total of 6 π-electrons (3 from nitrogen and 3 from the bonds formed), satisfying Huckel's rule (for n = 1: 4(1) + 2 = 6).

**Hint:** Remember the criteria for aromaticity and how to apply Huckel's rule.

### Step 5: Conclusion on Assertion and Reason
- **Assertion (A)**: Borazole is aromatic in nature. This is correct based on our analysis.
- **Reason (R)**: Nitrogen contributes π-electrons to the system. This is also correct as nitrogen donates its lone pairs, contributing to the π-electron system.

Since both the assertion and reason are correct, and the reason explains the assertion, the final conclusion is that both A and R are correct, and R is the correct explanation of A.

**Final Answer:** Both A and R are correct, and R is the correct explanation of A.