The incorrect statement (s0 among the following is //are :

Options

A. `Nci_5` does not exist buyt `PCl_5` does
B. Lead prefers to form tetravalent compounds
C. The three `C-O` bonds are not equal in the `CO_3^(2-)` ion.
D. Both ` O_2^(o+)` and `NO` are paramagnetic .

Explanation

To solve the question regarding the incorrect statements among the provided options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Evaluate Statement A: "nCl5 does not exist but PCl5 exists."**
- **Analysis:** Nitrogen (N) does not have vacant d orbitals, which means it cannot expand its valency beyond four. Therefore, nCl5 cannot exist. On the other hand, phosphorus (P) has vacant d orbitals and can form PCl5.
- **Conclusion:** This statement is **true**.

2. **Evaluate Statement B: "Lead prefers to form tetravalent compounds."**
- **Analysis:** Lead (Pb) typically forms bivalent compounds (Pb^2+) rather than tetravalent compounds (Pb^4+). The preference for bivalency is due to the inert pair effect, where the s-electrons are less available for bonding in heavier p-block elements.
- **Conclusion:** This statement is **false** (incorrect).

3. **Evaluate Statement C: "The three carbon-oxygen bonds are not equal in CO3^2- ion."**
- **Analysis:** In the carbonate ion (CO3^2-), the three carbon-oxygen bonds are equivalent due to resonance. The negative charge is delocalized over the three oxygen atoms, leading to equal bond lengths.
- **Conclusion:** This statement is **false** (incorrect).

4. **Evaluate Statement D: "Both O2+ and NO are paramagnetic."**
- **Analysis:** O2+ has unpaired electrons and is paramagnetic. Similarly, nitric oxide (NO) also has an unpaired electron, making it paramagnetic as well.
- **Conclusion:** This statement is **true**.

### Final Answer:
The incorrect statements among the options are **B and C**.