Which one is the electron deficient compound ?

Options

A. ICI
B. `NH_(3)`
C. `BCl_(3)`
D. `PCl_(3)`

Explanation

To determine which compound is electron deficient, we need to analyze the valence electrons and bonding of each compound given in the question. Let's go through the compounds one by one.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds mentioned are ICl, NH3, BCl3, and PCl3.

2. **Analyze ICl (Iodine monochloride)**:
- Iodine (I) has 7 valence electrons.
- Chlorine (Cl) has 7 valence electrons.
- When ICl forms, iodine shares one electron with chlorine, resulting in 8 electrons around chlorine and 8 electrons around iodine (6 from lone pairs and 2 from the bond).
- **Conclusion**: Both iodine and chlorine have complete octets. **Not electron deficient**.

3. **Analyze NH3 (Ammonia)**:
- Nitrogen (N) has 5 valence electrons.
- Each hydrogen (H) has 1 valence electron.
- In NH3, nitrogen shares its electrons with three hydrogens, resulting in 8 electrons around nitrogen (2 from the bond pairs with H and 2 from the lone pair).
- **Conclusion**: Nitrogen has a complete octet. **Not electron deficient**.

4. **Analyze BCl3 (Boron trichloride)**:
- Boron (B) has 3 valence electrons.
- Each chlorine (Cl) has 7 valence electrons.
- In BCl3, boron forms three bonds with three chlorine atoms, resulting in only 6 electrons around boron (3 from the bonds).
- **Conclusion**: Boron does not have a complete octet (only 6 electrons). **Electron deficient compound**.

5. **Analyze PCl3 (Phosphorus trichloride)**:
- Phosphorus (P) has 5 valence electrons.
- Each chlorine (Cl) has 7 valence electrons.
- In PCl3, phosphorus shares its electrons with three chlorine atoms, resulting in 8 electrons around phosphorus (2 from the bond pairs and 2 from the lone pair).
- **Conclusion**: Phosphorus has a complete octet. **Not electron deficient**.

### Final Answer:
The electron deficient compound among the given options is **BCl3 (Boron trichloride)**.

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