Assertion:Cyclobutane is less stable than cyclopentane.
Reason : Presence of bent bonds causes "loss of orbital overlap"

Options

A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. if assertion is true but reason is false
D. If the assertion and reason both are false

Answer

To analyze the assertion and reason provided in the question, we can break down the solution into a series of steps:

### Step 1: Understand the Structures of Cyclobutane and Cyclopentane
- Cyclobutane is a four-membered ring, while cyclopentane is a five-membered ring.
- Both compounds consist of carbon atoms that are sp³ hybridized.

### Step 2: Analyze the Bond Angles
- In an ideal tetrahedral geometry, the bond angle should be approximately 109.5 degrees.
- In cyclobutane, due to the ring strain, the bond angles are approximately 90 degrees.
- In cyclopentane, the bond angles are slightly less than 109.5 degrees, around 104 degrees.

### Step 3: Evaluate Stability Based on Bond Angles
- The significant deviation of bond angles in cyclobutane (90 degrees) from the ideal tetrahedral angle (109.5 degrees) introduces angle strain, making cyclobutane less stable.
- Cyclopentane, with bond angles closer to the ideal tetrahedral angle, experiences less angle strain and is therefore more stable than cyclobutane.

### Step 4: Assess the Assertion
- The assertion states that "Cyclobutane is less stable than cyclopentane." This statement is true based on the analysis of bond angles and stability.

### Step 5: Evaluate the Reason
- The reason provided states that "Presence of bent bonds causes 'loss of orbital overlap.'"
- While it is true that bent bonds can lead to some degree of strain, the statement about loss of orbital overlap is misleading. The overlap still occurs, but the strain affects stability.
- Therefore, this reason is false.

### Step 6: Conclusion
- The assertion is true, while the reason is false. Thus, the correct answer is that the assertion is true, but the reason is false.

### Final Answer
The correct option is that the assertion is true, but the reason is false.

---