Assertion : `K_(2)[Ni(EDTA)]` is more stable than `K_(3)[Al(C_(2)O_(4))_(3)]`.
Reason : Ni is a transition element while Al is a non-transition element .

Options

A. If both Assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false

Explanation

To solve the question regarding the stability of the coordination compounds \( K_2[Ni(EDTA)] \) and \( K_3[Al(C_2O_4)_3] \), we will analyze both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- \( K_2[Ni(EDTA)] \): This compound consists of nickel (Ni) coordinated with EDTA (ethylenediaminetetraacetic acid), which is a hexadentate ligand. This means it can form multiple bonds with the metal ion.
- \( K_3[Al(C_2O_4)_3] \): This compound consists of aluminum (Al) coordinated with oxalate ions (C2O4), which are bidentate ligands.

2. **Stability of Coordination Compounds**:
- The stability of coordination compounds is often influenced by the number of coordination sites occupied by ligands. More coordination sites typically lead to greater stability due to the chelate effect.
- In \( K_2[Ni(EDTA)] \), the EDTA ligand can form six bonds with nickel, leading to a very stable chelate complex.
- In contrast, \( K_3[Al(C_2O_4)_3] \) has three bidentate oxalate ligands, which can form a maximum of six bonds, but the overall stability is generally lower than that of a complex with a hexadentate ligand like EDTA.

3. **Evaluating the Assertion**:
- The assertion states that \( K_2[Ni(EDTA)] \) is more stable than \( K_3[Al(C_2O_4)_3] \). Given that EDTA forms a stronger chelate complex than oxalate, this assertion is **true**.

4. **Evaluating the Reason**:
- The reason states that nickel is a transition element while aluminum is a non-transition element. While it is true that nickel is a transition metal and aluminum is not, this fact alone does not adequately explain the difference in stability between the two complexes.
- The stability difference is primarily due to the nature of the ligands (EDTA vs. oxalate) and the chelate effect, rather than solely the classification of the metal ions.

5. **Conclusion**:
- The assertion is true, but the reason provided does not correctly explain the assertion. Therefore, we conclude that while both statements are true, the reason is not a valid explanation for the assertion.

### Final Answer:
- The assertion is true, and the reason is true but does not explain the assertion.