Assertion: Optical isomerism is not shown by square planar complexes .
Reason :Square planar complexes do not possess chiral structures.

Options

A. If both `(A)` and ` (R )` are correct and `(R )` is the correct explanation of `(A ) ` .
B. If both `(A)` and ` (R )` are correct and `(R )` is not the correct explanation of `(A ) ` .
C. If`(A)` is correct, but `( R )` is incorrect .
D. Both `(A)` and `(R ) ` are incorrect .

Answer

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

**Assertion:** Optical isomerism is not shown by square planar complexes.
**Reason:** Square planar complexes do not possess chiral structures.

### Step-by-Step Solution:

1. **Understanding Optical Isomerism:**
- Optical isomerism occurs when a compound can exist in two forms that are mirror images of each other, known as enantiomers. For a compound to exhibit optical isomerism, it must have a chiral center and lack any symmetry.

**Hint:** Recall that chirality is a key factor in optical isomerism.

2. **Chirality in Square Planar Complexes:**
- Square planar complexes are typically formed by d8 metal ions and have a specific geometry. In a square planar arrangement, the central metal atom is surrounded by four ligands positioned at the corners of a square.

**Hint:** Visualize the geometry of square planar complexes to understand their symmetry.

3. **Chiral Centers:**
- A chiral center is defined as a carbon atom (or any atom) that is bonded to four different groups. While it is theoretically possible for a square planar complex to have a chiral center, the presence of symmetry in the arrangement can negate chirality.

**Hint:** Consider how symmetry affects the overall structure of the complex.

4. **Symmetry in Square Planar Complexes:**
- Square planar complexes often have a plane of symmetry. This means that if you were to draw a line through the center of the complex, the two halves would be mirror images of each other. As a result, even if there are four different ligands, the symmetry leads to an achiral structure.

**Hint:** Think about how symmetry can lead to achirality even with different ligands.

5. **Conclusion:**
- Since square planar complexes can have a plane of symmetry, they do not exhibit optical isomerism despite potentially having a chiral center. Therefore, the assertion is correct, and the reason provided correctly explains the assertion.

**Final Answer:** Both the assertion and reason are correct, and the reason is the correct explanation of the assertion.

### Answer Option:
- Option A: Assertion is correct, Reason is correct, and Reason is the correct explanation of Assertion.