In the following questions, a statement of assertion (A) is followed by a statement of reason (R )
A: bond angle of `BF_(3) and NF_(3)` are different.
R : Both the molecules are having different shape

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 (A) and the reason (R) given in the problem.

### Step-by-Step Solution:

1. **Identify the Assertion and Reason**:
- Assertion (A): The bond angles of BF₃ and NF₃ are different.
- Reason (R): Both the molecules have different shapes.

2. **Analyze the Assertion**:
- BF₃ (Boron Trifluoride):
- Boron is the central atom with 3 outer electrons.
- It forms 3 bonds with fluorine atoms, using all 3 electrons.
- The hybridization of BF₃ is sp² (3 bond pairs, 0 lone pairs).
- The shape of BF₃ is trigonal planar, which has a bond angle of 120°.

- NF₃ (Nitrogen Trifluoride):
- Nitrogen is the central atom with 5 outer electrons.
- It forms 3 bonds with fluorine atoms and has 1 lone pair of electrons.
- The hybridization of NF₃ is sp³ (3 bond pairs, 1 lone pair).
- The shape of NF₃ is trigonal pyramidal due to the presence of the lone pair.
- The bond angle in NF₃ is less than 109.5° (actual bond angle is approximately 102° due to lone pair-bond pair repulsion).

3. **Conclusion on the Assertion**:
- The bond angles of BF₃ (120°) and NF₃ (approximately 102°) are indeed different. Therefore, the assertion is true.

4. **Analyze the Reason**:
- The reason states that both molecules have different shapes.
- BF₃ has a trigonal planar shape, while NF₃ has a trigonal pyramidal shape.
- Since the shapes are different, this contributes to the difference in bond angles.

5. **Conclusion on the Reason**:
- The reason is also true as the different shapes of the molecules are indeed responsible for the difference in bond angles.

6. **Determine the Relationship**:
- Since both the assertion and reason are true, and the reason correctly explains the assertion, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

### Final Answer:
The correct option is **Option 1**: Both assertion and reason are true, and the reason is the correct explanation of the assertion.