Assertion: Rotation about C=C is restricted.
Reason: Electron charge cloud of the `pi` bond is located above and below the plane of bonding atoms.

Options

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

Explanation

To solve the question, we need to analyze both the assertion and the reason provided:

### Step 1: Understand the Assertion
**Assertion:** Rotation about C=C is restricted.

- In a carbon-carbon double bond (C=C), there are two types of bonds: a sigma (σ) bond and a pi (π) bond.
- The σ bond allows for free rotation because it is formed by the head-on overlap of orbitals.
- However, the π bond is formed by the sideways overlap of p-orbitals, which creates a region of electron density above and below the plane of the atoms involved in the bond.
- This arrangement leads to restricted rotation because any attempt to rotate the double bond would disrupt the overlap of the p-orbitals, breaking the π bond.

**Conclusion for Step 1:** The assertion is correct; rotation about C=C is indeed restricted.

### Step 2: Understand the Reason
**Reason:** Electron charge cloud of the π bond is located above and below the plane of bonding atoms.

- The reason describes the spatial orientation of the π bond's electron cloud.
- While it is true that the electron cloud of the π bond is located above and below the plane of bonding atoms, this statement does not directly explain why rotation is restricted.
- The restriction on rotation is primarily due to the need for the p-orbitals to maintain their parallel orientation for effective overlap. If one part of the molecule rotates, it can lead to a misalignment of the p-orbitals, which would disrupt the π bond.

**Conclusion for Step 2:** The reason is true, but it does not correctly explain the assertion.

### Final Conclusion
Both the assertion and the reason are correct statements, but the reason does not adequately explain the assertion. Therefore, the correct answer is that both statements are true, but the reason is not the correct explanation for the assertion.