Which of the following statement is incorrect?

Options

A. Ozone is violet-black in solid state
B. Ozone is diamagnetic gas
C. `NOCl and ONO^(-)` are isoelectronic
D. Ozone molecule is bent

Answer

To determine which statement is incorrect, let's analyze each option one by one.

1. **Ozone is violet-black in solid form.**
- Ozone (O₃) does appear as a violet-black solid when it is in its solid state. This statement is **correct**.

2. **Ozone is a diamagnetic gas.**
- Ozone has a total of 24 electrons (8 from each oxygen atom). Since it has an even number of electrons and no unpaired electrons in its molecular orbital configuration, ozone is indeed diamagnetic. This statement is **correct**.

3. **NOCl and O₂⁻ are isoelectronic.**
- To check if NOCl and O₂⁻ are isoelectronic, we need to count their total number of electrons.
- For NOCl:
- Nitrogen (N) has 7 electrons.
- Oxygen (O) has 8 electrons.
- Chlorine (Cl) has 17 electrons.
- Total = 7 + 8 + 17 = 32 electrons.
- For O₂⁻:
- Each oxygen atom has 8 electrons, and since there are two oxygen atoms, that gives us 16 electrons.
- The O₂⁻ ion has gained an extra electron, so it has 16 + 1 = 17 electrons.
- Total = 17 electrons.
- Since NOCl has 32 electrons and O₂⁻ has 17 electrons, they are not isoelectronic. This statement is **incorrect**.

4. **Ozone molecule is bent.**
- The ozone molecule has a bent structure with a bond angle of approximately 116.8 degrees. This statement is **correct**.

Based on the analysis, the incorrect statement is:

**NOCl and O₂⁻ are isoelectronic.**

### Final Answer:
The incorrect statement is: **NOCl and O₂⁻ are isoelectronic.**

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