In which of the following geometrical isomerism is possible ?

Options

A. `CH_(3)CH=C(CH_(3))_(2)`
B. `C_(6)H_(5)N=NC_(6)H_(5)`
C. `CH_(3)CH=CH_(2)`
D. All of these

Answer

To determine which of the given compounds can exhibit geometrical isomerism (GI), we need to follow these steps:

### Step 1: Understand the Conditions for Geometrical Isomerism
Geometrical isomerism occurs under two main conditions:
1. There must be restricted rotation around a bond (usually a double bond).
2. The substituents attached to the atoms involved in the double bond must be different.

### Step 2: Analyze the First Compound
- The first compound has a double bond and two methyl groups attached to one of the carbon atoms.
- Since both substituents on this carbon are the same (methyl groups), there is no possibility for geometrical isomerism.
- **Conclusion**: GI is not possible for the first compound.

### Step 3: Analyze the Second Compound
- The second compound contains a double bond between two nitrogen atoms, with one nitrogen having a lone pair and a phenyl group attached.
- The other nitrogen also has a phenyl group attached.
- Here, we have different substituents (lone pair and phenyl group) on one nitrogen, which allows for the formation of geometrical isomers (cis and trans forms).
- **Conclusion**: GI is possible for the second compound.

### Step 4: Analyze the Third Compound
- The third compound has a double bond, but both substituents on one of the carbon atoms are hydrogen atoms.
- Since both substituents are the same, there is no possibility for geometrical isomerism.
- **Conclusion**: GI is not possible for the third compound.

### Final Conclusion
Among the three compounds analyzed, only the second compound shows geometrical isomerism.

### Summary of the Answer
- **Only the second compound shows geometrical isomerism.**

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