In which type of molecule, the dipole moment will be nonzero :-

Options

A. `AB_(2)L_(2)`
B. `AB_(2)L_(3)`
C. `AB_(4)L_(2)`
D. `AB_(4)`

Answer

To determine in which type of molecule the dipole moment will be non-zero, we need to analyze the molecular geometries and the presence of lone pairs on the central atom. Here's a step-by-step solution:

### Step 1: Understand the concept of dipole moment
The dipole moment is a measure of the separation of positive and negative charges in a molecule. A molecule has a non-zero dipole moment if there is an asymmetrical distribution of charge, meaning that the bond dipoles do not cancel each other out.

### Step 2: Analyze the given molecular types
We will analyze the following types of molecules based on their general formulas:
- AB2L2
- AB2L3
- AB4
- AB3L

Where A is the central atom, B is a bonded atom, and L represents lone pairs on the central atom.

### Step 3: Evaluate AB2L2
- **Geometry**: Bent or V-shaped
- **Lone pairs**: 2 lone pairs
- **Bonding pairs**: 2 bonding pairs
- **Dipole moment**: The bond dipoles from the two B atoms do not cancel out due to the presence of lone pairs, resulting in a non-zero dipole moment.

### Step 4: Evaluate AB2L3
- **Geometry**: T-shaped
- **Lone pairs**: 3 lone pairs
- **Bonding pairs**: 2 bonding pairs
- **Dipole moment**: The bond dipoles from the two B atoms are arranged in such a way that they cancel each other out, resulting in a zero dipole moment.

### Step 5: Evaluate AB4
- **Geometry**: Tetrahedral
- **Lone pairs**: 0 lone pairs
- **Bonding pairs**: 4 bonding pairs
- **Dipole moment**: The bond dipoles from the four B atoms are symmetrically arranged, leading to a cancellation of dipole moments, resulting in a zero dipole moment.

### Step 6: Evaluate AB3L
- **Geometry**: Trigonal pyramidal
- **Lone pairs**: 1 lone pair
- **Bonding pairs**: 3 bonding pairs
- **Dipole moment**: The presence of the lone pair creates an asymmetrical distribution of charge, resulting in a non-zero dipole moment.

### Conclusion
From the analysis, we find that:
- The molecule AB2L2 has a non-zero dipole moment.
- The molecule AB3L also has a non-zero dipole moment.
- The molecules AB2L3 and AB4 have a zero dipole moment.

Thus, the correct answer is that the dipole moment will be non-zero in the molecules of type **AB2L2** and **AB3L**.

### Final Answer
The type of molecule where the dipole moment will be non-zero is **AB2L2** and **AB3L**.