Assertion:- All compounds having C=C bond exhibit geometrical isomerism
Reason:- Rotation about C=C is restricted

Options

A. If both Assertion `&` Reason are True `&` the Reason is a correct explanation of the Assertion.
B. If both Assertion `&` Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion is false `&` Reason is true.

Answer

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Understanding the Assertion
The assertion states: "All compounds having C=C bond exhibit geometrical isomerism."

- **Analysis**: Not all compounds with a C=C bond exhibit geometrical isomerism. For geometrical isomerism to occur, the two carbon atoms in the double bond must have different substituents. If both carbon atoms have identical substituents, then geometrical isomerism cannot occur.

### Step 2: Understanding the Reason
The reason states: "Rotation about C=C is restricted."

- **Analysis**: This statement is true. The presence of a double bond (C=C) restricts rotation around the bond due to the pi bond formed in addition to the sigma bond. This restriction is what allows for the possibility of geometrical isomers.

### Step 3: Conclusion
- Since the assertion is false (not all compounds with C=C exhibit geometrical isomerism), but the reason is true (rotation about C=C is indeed restricted), we conclude that:
- **Assertion**: False
- **Reason**: True

### Final Answer
The correct answer is that the assertion is false, and the reason is true.

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