Question

The correct statements from the following are :
(A) $ Tl^{3+} $ is a powerful oxidising agent
(B) $ Al^{3+} $ does not get reduced easily
(C) Both $ Al^{3+} $ and $ Tl^{3+} $ are very stable in solution
(D) $ Tl^+ $ is more stable than $ Tl^{3+} $
(E) $ Al^{3+} $ and $ Tl^+ $ are highly stable
Choose the correct answer from the options given below :

• A. (A), (B), (C), (D) and (E)
• B. (A), (B), (D) and (E) only
• C. (B), (D) and (E) only
• D. (A), (C) and (D) only

Hint:

Remember the inert pair effect, which leads to the increased stability of the lower oxidation state (+1) for heavier p-block elements like Tl. Aluminum, being a lighter element in Group 13, primarily exhibits the +3 oxidation state due to the ready participation of all its valence electrons in bonding.

Answer 1

The Correct Option is B

To address this question, each statement regarding the oxidation states, stability, and redox behavior of aluminum (\( \text{Al} \)) and thallium (\( \text{Tl} \)) ions must be evaluated:

1. Statement (A): \( \text{Tl}^{3+} \) is a potent oxidizing agent
   The \( \text{Tl}^{3+} \) ion functions as a strong oxidizing agent due to its propensity to accept electrons, reducing to \( \text{Tl}^{+} \). This reduction is favored because the \( \text{Tl}^{1+} \) state is more stable owing to its electronic configuration. Consequently, statement (A) is validated.
2. Statement (B): \( \text{Al}^{3+} \) resists reduction
   The \( \text{Al}^{3+} \) ion exhibits chemical stability due to its noble gas electron configuration. It is not readily reduced as such a process necessitates energy input to populate higher energy orbitals. Therefore, statement (B) is confirmed.
3. Statement (C): \( \text{Al}^{3+} \) and \( \text{Tl}^{3+} \) exhibit high stability in solution
   While \( \text{Al}^{3+} \) is stable, \( \text{Tl}^{3+} \) is not highly stable in solution, as it tends to reduce to the more stable \( \text{Tl}^{+} \) state. Thus, statement (C) is invalidated.
4. Statement (D): \( \text{Tl}^{+} \) demonstrates greater stability than \( \text{Tl}^{3+} \)
   This assertion is accurate because \( \text{Tl}^{+} \) possesses a half-filled \( 6s \) orbital, which confers additional stability. Accordingly, statement (D) is validated.
5. Statement (E): \( \text{Al}^{3+} \) and \( \text{Tl}^{+} \) are exceptionally stable
   As previously elucidated, both \( \text{Al}^{3+} \) and \( \text{Tl}^{+} \) are stable owing to their respective electronic configurations, rendering statement (E) accurate.

Following the detailed analysis, the collection of correct statements comprises (A), (B), (D), and (E).