The heavier elements of group 13, 14 and 15 besides their group oxidation state exhibit another oxidation state which is two units lower than the group oxidation state. The stability of lower oxidation state increases down the group.
The display of lower oxidation state is due to inert pair effect.
QWhich of the following statements is incorrect?

Options

A. Boron shows only +3 oxidation state
B. n `Ga^(+3)` oxidation state is more stable than + 1 oxidation state
C. In `Sn^(+3)` oxidation state is more stable than +4 oxidation state
D. in `Ti^(+1)` oxidation state is more stable than +3 oxidation state

Answer

To solve the question regarding the incorrect statement about the oxidation states of heavier elements in groups 13, 14, and 15, we will analyze each statement provided in the question step by step.

### Step 1: Understand the Group Oxidation States
The heavier elements of groups 13, 14, and 15 can exhibit two oxidation states: the group oxidation state and a lower oxidation state, which is typically two units lower. The stability of the lower oxidation state increases down the group due to the inert pair effect.

### Step 2: Analyze Each Statement
1. **Boron shows only +3 oxidation state.**
- This statement is **incorrect**. Boron primarily exhibits a +3 oxidation state, but it can also show a +1 oxidation state in certain compounds.

2. **In Ga, +3 oxidation state is more stable than +1 oxidation state.**
- This statement is **correct**. Gallium, being higher in the group, favors the +3 oxidation state over the +1 oxidation state.

3. **In Sn, +2 oxidation state is more stable than +4 oxidation state.**
- This statement is **incorrect**. For tin (Sn), the +4 oxidation state is generally more stable than the +2 oxidation state due to the inert pair effect.

4. **In Tl, +1 oxidation state is more stable than +3 oxidation state.**
- This statement is **correct**. Thallium (Tl) shows a preference for the +1 oxidation state over the +3 oxidation state due to the inert pair effect.

### Step 3: Identify the Incorrect Statement
From the analysis, the statements about boron and tin are incorrect. However, since we are looking for a single incorrect statement, we can conclude that the statement regarding Sn (+2 being more stable than +4) is the most clearly incorrect in the context of the question.

### Conclusion
The incorrect statement is: **"In Sn, +2 oxidation state is more stable than +4 oxidation state."**

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