Thallous chloride is more stable than thallic chloride because of

Options

A. More ionic character
B. Larger size of `T1^+` ion
C. High hydration energy of `Ti^+` ion
D. Inert pair effect

Answer

To determine why thallous chloride (TlCl) is more stable than thallic chloride (TlCl₃), we can analyze the oxidation states of thallium in both compounds and the factors affecting their stability.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Thallous chloride is TlCl (thallium in +1 oxidation state).
- Thallic chloride is TlCl₃ (thallium in +3 oxidation state).

2. **Understand Oxidation States**:
- In TlCl, thallium is in the +1 oxidation state.
- In TlCl₃, thallium is in the +3 oxidation state.
- Generally, lower oxidation states tend to be more stable for heavier elements in the periodic table.

3. **Stability of Oxidation States**:
- For thallium, the +1 oxidation state (thallous) is more stable than the +3 oxidation state (thallic).
- This trend is observed because the +1 state allows for a more favorable electron configuration.

4. **Inert Pair Effect**:
- The inert pair effect refers to the tendency of the outermost s-electrons to remain non-bonding in heavier elements.
- In thallium, the presence of filled d and f orbitals leads to poor shielding of the nucleus, making it energetically favorable for thallium to lose only one electron (to achieve +1 state) rather than three (to achieve +3 state).

5. **Electronic Configuration**:
- The electronic configuration of thallium is [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹.
- The 6s² electrons are less involved in bonding due to the inert pair effect, leading to greater stability in the +1 oxidation state.

6. **Conclusion**:
- Thallous chloride (TlCl) is more stable than thallic chloride (TlCl₃) primarily due to the inert pair effect, which stabilizes the +1 oxidation state of thallium.

### Final Answer:
Thallous chloride is more stable than thallic chloride because of the inert pair effect, which stabilizes the +1 oxidation state of thallium compared to the +3 oxidation state.

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