Question

For which of the following \(+3\) oxidation state is highly oxidizing in character?

• A. Al
• B. Ga
• C. In
• D. Tl

Hint:

Due to the inert pair effect, the stability of the \(+1\) oxidation state increases down Group 13. Hence \(Tl^{3+}\) readily reduces to \(Tl^+\) and acts as a strong oxidizing agent.

Answer 1

The Correct Option is D

Step 1: Apply inert pair effect down Group 13.
Tl⁺ (6s² inert pair retained) is much more stable than Tl³⁺. Therefore Tl³⁺ + 2e⁻ → Tl⁺ occurs readily, making Tl(III) a strong oxidant.

Step 2: Final Answer:
Tl (option 4).