Choose the INCORRECT statements from the following -

Options

A. Bond angles are not affected in `BF_(3)` due to back bonding
B. Bond angles are affected in `PF_(3)` due to back bonding
C. Bond angles are not affected in `B(O Me)_(3)` due to back bonding
D. none of these

Answer

To solve the question of identifying the incorrect statements regarding bond angles and back bonding, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Statement 1: Bond angles are not affected in BF3 due to back bonding.**
- **Analysis:**
- BF3 has a trigonal planar geometry with bond angles of 120 degrees.
- In BF3, there is no lone pair on the boron atom, and the presence of back bonding does not alter the bond angles significantly.
- Therefore, this statement is **correct**.

2. **Statement 2: Bond angles are affected in PF3 due to back bonding.**
- **Analysis:**
- PF3 has a trigonal pyramidal shape due to the presence of a lone pair on phosphorus.
- The lone pair causes repulsion, which reduces the bond angles from the ideal tetrahedral angle of 109.5 degrees.
- Thus, this statement is also **correct**.

3. **Statement 3: Bond angles are not affected in BOMe3 due to back bonding.**
- **Analysis:**
- BOMe3 (Boron trimethyl ether) has a structure where boron is bonded to three OMe groups.
- The presence of partial double bond character between boron and oxygen due to resonance leads to bond angle changes.
- The bond angles in BOMe3 are affected and are larger than the ideal tetrahedral angle due to repulsion between the double and single bonds.
- Therefore, this statement is **incorrect**.

4. **Statement 4: None of these.**
- **Analysis:**
- Since we have identified Statement 3 as incorrect, this statement is also **incorrect** because it claims that none of the previous statements are incorrect.

### Conclusion:
The incorrect statement among the options provided is **Statement 3**: "Bond angles are not affected in BOMe3 due to back bonding."

### Final Answer:
The answer to the question is **Statement 3**.

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