Geometrical isomerism results because molecule has

Options

A. rotates the plane of polarized light
B. has a plane of symmetry
C. has a centre of symmetry
D. has two dissimilar groups attached to both ends of double bond

Answer

To answer the question "Geometrical isomerism results because a molecule has:", we need to understand the concept of geometrical isomerism and the conditions required for it to occur.

### Step-by-Step Solution:

1. **Definition of Geometrical Isomerism**:
Geometrical isomerism, also known as cis-trans isomerism, occurs in compounds that have the same molecular formula but differ in the spatial arrangement of atoms or groups around a double bond or a ring structure.

**Hint**: Remember that geometrical isomers have the same connectivity but different spatial arrangements.

2. **Requirement for Geometrical Isomerism**:
For geometrical isomerism to occur, the molecule must have a double bond (C=C) or a cyclic structure. This is because the double bond or ring prevents rotation, leading to different arrangements of substituents.

**Hint**: Think about how rotation around a single bond differs from a double bond.

3. **Presence of Dissimilar Groups**:
Specifically, geometrical isomerism is observed when there are two dissimilar groups attached to each carbon atom of the double bond. This allows for the formation of cis (same side) and trans (opposite side) configurations.

**Hint**: Identify the groups attached to the double bond and see if they are the same or different.

4. **Conclusion**:
Therefore, the correct answer to the question is that geometrical isomerism results because the molecule has two dissimilar groups attached to both ends of the double bond.

**Hint**: Look for the arrangement of groups around the double bond to determine if they are dissimilar.

### Final Answer:
Geometrical isomerism results because a molecule has two dissimilar groups attached to both ends of the double bond.