A : `NH_(3)` is more polar than `NF_(3)` .
R : `NF_(3)` cannot be hydrolysed .

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2)
C. If Assertion is true statement but Reason is false , then mark (3)
D. If both Assertion and Reason are false statements , then mark (4)

Answer

To analyze the given statements regarding the polarity of `NH3` and `NF3`, we will break down the assertion and reason step by step.

### Step 1: Understanding the Assertion
The assertion states that `NH3` (ammonia) is more polar than `NF3` (nitrogen trifluoride).

**Explanation:**
- **Polarity** is determined by the difference in electronegativity between the atoms in a molecule and the molecular geometry.
- In `NH3`, the nitrogen atom is bonded to three hydrogen atoms. The electronegativity of nitrogen is higher than that of hydrogen, creating a dipole moment directed towards nitrogen.
- In `NF3`, the nitrogen atom is bonded to three fluorine atoms. Fluorine is more electronegative than nitrogen, which means the dipole moments of the N-F bonds are directed towards fluorine.

### Step 2: Analyzing the Dipole Moments
- In `NH3`, the dipole moments from the N-H bonds and the lone pair on nitrogen all point in the same direction, resulting in a significant net dipole moment.
- In `NF3`, the dipole moments from the N-F bonds point towards fluorine, while the lone pair on nitrogen points in the opposite direction. This results in a cancellation of some of the dipole moments, leading to a smaller net dipole moment.

### Conclusion for Step 1:
Thus, `NH3` is indeed more polar than `NF3` due to the additive effect of the dipole moments in `NH3` compared to the cancellation effect in `NF3`.

### Step 3: Understanding the Reason
The reason states that `NF3` cannot be hydrolyzed.

**Explanation:**
- Hydrolysis involves the reaction of a compound with water, which typically requires the ability of the compound to accept a lone pair of electrons from water.
- In the case of `NF3`, neither nitrogen nor fluorine has d-orbitals that can accommodate additional electron pairs. Therefore, `NF3` cannot react with water to form hydrolyzed products.

### Conclusion for Step 2:
While the reason is correct, it does not explain why `NH3` is more polar than `NF3`. The inability of `NF3` to hydrolyze is unrelated to its polarity.

### Final Conclusion:
- Both the assertion and the reason are true.
- However, the reason is not the correct explanation for the assertion.

### Answer:
The correct option is: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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