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 solve the question, we need to analyze the assertion and reason statements provided:

**Assertion (A):** NH₃ is more polar than NF₃.
**Reason (R):** NF₃ cannot be hydrolyzed.

### Step 1: Analyze the Assertion (A)
1. **Understanding Polarity:**
- Polarity in molecules is determined by the difference in electronegativity between the atoms and the molecular geometry.
- NH₃ (ammonia) has a nitrogen atom bonded to three hydrogen atoms and one lone pair of electrons, which creates a net dipole moment.

2. **Molecular Geometry of NH₃:**
- NH₃ has a trigonal pyramidal shape due to the presence of the lone pair on nitrogen.
- The dipole moments from the N-H bonds add up to create a significant overall dipole moment pointing towards the nitrogen atom.

3. **Understanding NF₃:**
- NF₃ (nitrogen trifluoride) has a similar trigonal pyramidal shape, but the electronegativity of fluorine is much higher than that of hydrogen.
- The dipole moments from the N-F bonds also add up, but since fluorine pulls electron density away from nitrogen, the overall dipole moment is directed towards fluorine.

4. **Comparing Dipole Moments:**
- In NH₃, the lone pair on nitrogen contributes to the dipole moment, making NH₃ more polar than NF₃.
- Therefore, the assertion that NH₃ is more polar than NF₃ is **true**.

### Step 2: Analyze the Reason (R)
1. **Understanding Hydrolysis:**
- Hydrolysis refers to the reaction of a substance with water, often resulting in the formation of hydroxides or other products.
- For a molecule to undergo hydrolysis, it typically needs to have a lone pair that can coordinate with water or other reactants.

2. **Examining NF₃:**
- NF₃ does not have d-orbitals available for bonding, and the nitrogen atom's lone pair is not available for donation because of the strong electronegativity of fluorine.
- As a result, NF₃ cannot easily interact with water to undergo hydrolysis.

3. **Conclusion about the Reason:**
- The statement that NF₃ cannot be hydrolyzed is **true**.

### Step 3: Determine the Relationship Between A and R
1. **Correctness of A and R:**
- Both the assertion (A) and reason (R) are true.
- However, the reason provided (R) does not explain why NH₃ is more polar than NF₃; it simply states a fact about NF₃.

### Final Conclusion
- Since both statements are true but the reason does not explain the assertion, the correct option is:
**Option 2:** Both statements are true, but the reason is not the correct explanation of the assertion.

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