Pick out the incorrect statement.

Options

A. The geometry around 'N' atom in
trimethylamine is pyramidal
B. The geometry around N atom in
trisilylamine is planar
C. The nitrogen atom in trimethylamine is
`sp^(3)-` hybridized, whilst in trisilylamine
it is `sp^(2)-` hybridized.
D. Trisilylamine has donor properties whilst
trimethylamine has no donor properties

Answer

To solve the question of identifying the incorrect statement regarding trimethylamine and tricilylamine, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- **Trimethylamine (N(CH₃)₃)**: This molecule has a nitrogen atom bonded to three methyl groups (CH₃). The nitrogen atom has a lone pair of electrons, leading to a pyramidal geometry due to the repulsion between the lone pair and the bonding pairs.
- **Tricilylamine (N(SiH₃)₃)**: This molecule has a nitrogen atom bonded to three silyl groups (SiH₃). The nitrogen atom in this case can engage in back bonding with silicon, which has vacant d orbitals, leading to a planar geometry.

2. **Analyzing the Statements**:
- **Statement 1**: "The geometry around nitrogen atom in trimethylamine is pyramidal."
- **True**: The geometry is indeed pyramidal due to the lone pair on nitrogen.

- **Statement 2**: "The geometry around nitrogen atom in tricilylamine is planar."
- **True**: The geometry is planar due to back bonding with silicon.

- **Statement 3**: "The nitrogen atom in trimethylamine is sp³ hybridized, whereas in tricilylamine it is sp² hybridized."
- **True**: The nitrogen in trimethylamine is sp³ hybridized (due to three sigma bonds and one lone pair), while in tricilylamine, it is sp² hybridized due to the involvement in back bonding with silicon.

- **Statement 4**: "Tricilylamine has donor properties, while trimethylamine has no donor properties."
- **False**: This statement is incorrect. Trimethylamine has donor properties because it has a lone pair available for donation, while tricilylamine does not have donor properties due to the lone pair being involved in back bonding with silicon.

3. **Conclusion**:
- The incorrect statement is Statement 4: "Tricilylamine has donor properties, while trimethylamine has no donor properties."

### Final Answer:
The incorrect statement is: **Tricilylamine has donor properties, while trimethylamine has no donor properties.**

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