Which of the following species / molecules does not have same number of bond pairs and lone pairs ?

Options

A. `OCN^(-)`
B. `H_(2)O`
C. `C_(2)H_(2)Cl_(2)`
D. `O_(3)`

Explanation

To determine which of the following species or molecules does not have the same number of bond pairs and lone pairs, we will analyze each option step by step.

### Step 1: Analyze O-C-N (Oxygen Cyanide)
- **Lewis Structure**: The carbon (C) forms a triple bond with nitrogen (N) and a single bond with oxygen (O).
- **Bond Pairs**:
- Triple bond between C and N counts as 3 bond pairs.
- Single bond between C and O counts as 1 bond pair.
- Total bond pairs = 3 (C≡N) + 1 (C-O) = 4 bond pairs.
- **Lone Pairs**:
- Oxygen has 6 valence electrons and shares 1 with carbon, leaving it with 5 electrons, which means 3 lone pairs.
- Nitrogen has 5 valence electrons and shares 3 with carbon, leaving it with 2 electrons, which means 1 lone pair.
- Total lone pairs = 3 (O) + 1 (N) = 4 lone pairs.
- **Conclusion**: 4 bond pairs and 4 lone pairs.

### Step 2: Analyze H2O (Water)
- **Lewis Structure**: Oxygen (O) is bonded to two hydrogen (H) atoms.
- **Bond Pairs**:
- 2 single bonds (O-H) = 2 bond pairs.
- **Lone Pairs**:
- Oxygen has 6 valence electrons, 2 are used for bonding, leaving 4 electrons, which means 2 lone pairs.
- **Conclusion**: 2 bond pairs and 2 lone pairs.

### Step 3: Analyze C2H2Cl2 (Dichloroethene)
- **Lewis Structure**: Each carbon (C) is bonded to one hydrogen (H) and one chlorine (Cl), and they are connected by a double bond.
- **Bond Pairs**:
- 1 double bond (C=C) = 2 bond pairs.
- 2 single bonds (C-H) = 2 bond pairs.
- 2 single bonds (C-Cl) = 2 bond pairs.
- Total bond pairs = 2 (C=C) + 2 (C-H) + 2 (C-Cl) = 6 bond pairs.
- **Lone Pairs**:
- Each chlorine has 6 valence electrons and forms 1 bond, leaving 3 lone pairs each.
- Total lone pairs = 2 (Cl) x 3 = 6 lone pairs.
- **Conclusion**: 6 bond pairs and 6 lone pairs.

### Step 4: Analyze Ozone (O3)
- **Lewis Structure**: Ozone has a resonance structure where one oxygen is bonded to another oxygen with a double bond, and the third oxygen is bonded with a single bond.
- **Bond Pairs**:
- 1 double bond (O=O) = 2 bond pairs.
- 1 single bond (O-O) = 1 bond pair.
- Total bond pairs = 2 + 1 = 3 bond pairs.
- **Lone Pairs**:
- Each oxygen has lone pairs. The central oxygen has 1 lone pair, while the terminal oxygens each have 2 lone pairs.
- Total lone pairs = 1 (central O) + 2 (O1) + 2 (O2) = 5 lone pairs.
- **Conclusion**: 3 bond pairs and 5 lone pairs.

### Final Summary:
- O-C-N: 4 bond pairs, 4 lone pairs (same)
- H2O: 2 bond pairs, 2 lone pairs (same)
- C2H2Cl2: 6 bond pairs, 6 lone pairs (same)
- Ozone: 3 bond pairs, 5 lone pairs (different)

### Answer:
The species that does not have the same number of bond pairs and lone pairs is **Ozone (O3)**.

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