A: All square planar complexes can exhibit geometrical isomerism.
R: In square planar complexes metal assumes `sp^(3)` hybridisation.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. ) If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To analyze the given assertions and determine their validity, we will break down the concepts involved in square planar complexes, geometrical isomerism, and hybridization.

### Step 1: Understanding Geometrical Isomerism
Geometrical isomerism occurs when compounds have the same molecular formula but different spatial arrangements of atoms or groups. In coordination compounds, this often arises due to the different possible arrangements of ligands around a central metal atom.

**Hint:** Geometrical isomerism is related to the spatial arrangement of ligands around the metal center.

### Step 2: Square Planar Complexes and Geometrical Isomerism
Square planar complexes can exhibit geometrical isomerism, but not all square planar complexes will show this property. For example, in a square planar complex with the formula MA2B2, where A and B are different ligands, the arrangement can lead to different isomers (cis and trans forms). However, if all ligands are identical, there will be no isomerism.

**Hint:** Check if the ligands in the square planar complex are different to determine if geometrical isomerism is possible.

### Step 3: Evaluating Assertion A
The assertion states that "All square planar complexes can exhibit geometrical isomerism." This is incorrect because only certain square planar complexes (those with at least two different types of ligands) can exhibit geometrical isomerism. Thus, Assertion A is false.

**Hint:** Not all square planar complexes have different ligands; this affects their ability to show geometrical isomerism.

### Step 4: Understanding Hybridization in Square Planar Complexes
In square planar complexes, the central metal atom typically undergoes dsp² hybridization. This involves the mixing of one d orbital, one s orbital, and two p orbitals to form four equivalent hybrid orbitals arranged in a square planar geometry.

**Hint:** Remember that hybridization type can be determined by counting the number of ligands and the geometry they create.

### Step 5: Evaluating Assertion R
The assertion states that "In square planar complexes, the metal assumes sp³ hybridization." This is incorrect, as square planar complexes are characterized by dsp² hybridization, not sp³. Therefore, Assertion R is also false.

**Hint:** Hybridization types are linked to the geometry of the complex; square planar complexes do not use sp³ hybridization.

### Conclusion
Both assertions A and R are false.

1. **Assertion A**: False - Not all square planar complexes exhibit geometrical isomerism.
2. **Assertion R**: False - Square planar complexes involve dsp² hybridization, not sp³.