Question

For ozone molecule consider the following: 
1. It is a linear molecule with bond angle $180^\circ$
2. It is an angular molecule with bond angle $117^\circ$
3. The bond lengths of both O-O bonds are same
4. With respect to oxygen it is thermodynamically more stable 
The correct options are

• A. A and D
• B. B and C
• C. A and C
• D. B and D

Hint:

Key facts about ozone: 1. Bent molecular geometry (VSEPR)
2. Resonance hybrid structure
3. Endothermic formation ($\Delta H>0$)
4. Equal O-O bond lengths (1.28 Å)

Answer 1

The Correct Option is B

The ozone molecule (O$_3$) has a unique structure and properties: - Option A: False. O$_3$ has bent (angular) geometry due to lone pair repulsion.
- Option B: True. Bond angle is $117^\circ$.
- Option C: True. Resonance gives equal bond lengths.
- Option D: False. O$_3$ is thermodynamically unstable relative to O$_2$. Thus, the correct options are B and C. Answer: (2).

Answer 2

Step 1: Analyze the shape of the ozone molecule.
Ozone (\(\text{O}_3\)) has three oxygen atoms. It is known experimentally that ozone is not linear but has a bent (angular) shape.
The bond angle is approximately \(117^\circ\), which is less than \(120^\circ\) due to the presence of a lone pair on the central oxygen.

Step 2: Check the bond lengths of O–O bonds in ozone.
Both O–O bonds in ozone are equivalent and have the same bond length, which is an intermediate between a single and double bond due to resonance.

Step 3: Thermodynamic stability compared to oxygen.
Ozone is less thermodynamically stable than molecular oxygen (\(\text{O}_2\)) under normal conditions.

Step 4: Evaluate the given statements.
1. It is a linear molecule with bond angle \(180^\circ\) — Incorrect.
2. It is an angular molecule with bond angle \(117^\circ\) — Correct.
3. The bond lengths of both O–O bonds are same — Correct.
4. With respect to oxygen it is thermodynamically more stable — Incorrect.

Step 5: Conclusion.
The correct options are B and C.