Which of the following Lewis dot structure of `CO_2` is incorrect ?

Options

A. `:overset(..)underset(..)O-C-=O:`
B. `overset(..)underset(..)O=C=overset(..)underset(..)O:`
C. `:O-=C-overset(..)underset(..)O:`
D. None of these

Answer

To determine which Lewis dot structure of CO₂ is incorrect, we first need to understand the correct bonding in carbon dioxide.

### Step-by-Step Solution:

1. **Identify the Valence Electrons**:
- Carbon (C) has 4 valence electrons.
- Oxygen (O) has 6 valence electrons.
- Since there are two oxygen atoms, the total number of valence electrons in CO₂ is:
\[ 4 + 2 \times 6 = 16 \text{ valence electrons} \]

2. **Draw the Basic Structure**:
- Carbon is the central atom, and it will bond with two oxygen atoms.
- Initially, we can represent the bonds as single bonds:
\[ O - C - O \]

3. **Form Double Bonds**:
- To satisfy the octet rule, carbon can form double bonds with each oxygen atom. This means that carbon will share two of its electrons with each oxygen atom.
- The structure will now look like:
\[ O = C = O \]
- Each oxygen now has 4 electrons in bonds and 4 electrons as lone pairs (2 lone pairs), satisfying the octet rule.

4. **Consider Other Resonance Structures**:
- Another possible structure is to have a triple bond with one of the oxygen atoms and a single bond with the other. This can be represented as:
\[ O \equiv C - O \]
- In this case, the oxygen with the triple bond will have 1 lone pair, and the other oxygen will have 3 lone pairs.

5. **Evaluate Given Structures**:
- Now we need to evaluate the given options:
- **Option 1**: C≡O (triple bond) and O with 3 lone pairs. This structure is valid.
- **Option 2**: O=C=O (double bond between both oxygens and carbon). This structure is incorrect because it suggests that each oxygen has only 4 electrons, which does not satisfy the octet rule for oxygen.
- **Option 3**: C≡O (triple bond) and O with 1 lone pair. This structure is valid.

6. **Conclusion**:
- The incorrect Lewis dot structure for CO₂ is **Option 2** (O=C=O).