Few examples of the componds formed by chemical bonding are given below . Mark the incorrect example.

Options

A. A molecule with central atom devoid of octet - `BF_(3)`
B. A molecule with linear shape - `CO_(2)`
C. A non - polar covalent compound between two different atoms - `CH_(4)`
D. A molecule which is V- shaped with a bond angle `104.5^(@) - NH_(3)`

Answer

To determine the incorrect example of compounds formed by chemical bonding, we will analyze each given statement one by one.

### Step 1: Analyze BF3
- **Structure**: Boron trifluoride (BF3) has a trigonal planar structure.
- **Hybridization**: The hybridization of boron in BF3 is sp².
- **Valence Electrons**: Boron has 3 valence electrons (1s² 2s² 2p¹). In BF3, boron forms three bonds with fluorine atoms, using all its valence electrons.
- **Octet Rule**: Boron does not complete an octet in BF3 (it has only 6 electrons around it).
- **Conclusion**: This statement is correct; BF3 is indeed a molecule with a central atom (boron) that does not have a complete octet.

**Hint**: Check the valence electrons and bonding to see if the central atom satisfies the octet rule.

### Step 2: Analyze CO2
- **Structure**: Carbon dioxide (CO2) has a linear structure.
- **Hybridization**: The hybridization of carbon in CO2 is sp.
- **Bonding**: Carbon forms two double bonds with two oxygen atoms.
- **Conclusion**: This statement is correct; CO2 is a linear molecule.

**Hint**: Look at the hybridization and molecular geometry to confirm the shape of the molecule.

### Step 3: Analyze CH4
- **Structure**: Methane (CH4) has a tetrahedral structure.
- **Hybridization**: The hybridization of carbon in CH4 is sp³.
- **Polarity**: CH4 is a nonpolar molecule because of its symmetrical tetrahedral shape.
- **Conclusion**: This statement is correct; CH4 is a nonpolar covalent compound.

**Hint**: Consider the molecular geometry and symmetry to determine polarity.

### Step 4: Analyze Ammonia (NH3)
- **Structure**: Ammonia (NH3) has a pyramidal shape.
- **Hybridization**: The hybridization of nitrogen in NH3 is sp³.
- **Bond Angle**: The bond angle in NH3 is approximately 107 degrees due to the presence of a lone pair.
- **Incorrect Statement**: The statement claims that ammonia is v-shaped with a bond angle of 104.5 degrees, which is incorrect.
- **Conclusion**: This statement is incorrect; ammonia is not v-shaped and has a bond angle of 107 degrees.

**Hint**: Verify the molecular geometry and bond angles against known values for common molecules.

### Final Answer
The incorrect example among the given statements is the fourth one regarding ammonia (NH3).

### Summary of Steps:
1. Analyze BF3 for octet completion.
2. Confirm the linear structure of CO2.
3. Check the nonpolar nature of CH4.
4. Identify the incorrect description of ammonia's shape and bond angle.