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 solve this question, we need to analyze each statement based on our understanding of the oxidation states, stability, and redox behavior of aluminum (\( \text{Al} \)) and thallium (\( \text{Tl} \)) ions:

1. Statement (A): \( \text{Tl}^{3+} \) is a powerful oxidising agent
   The \( \text{Tl}^{3+} \) ion is indeed a powerful oxidizing agent due to its tendency to gain electrons and reduce to \( \text{Tl}^{+} \). This reduction from \( \text{Tl}^{3+} \) to \( \text{Tl}^{+} \) is favored because the \( \text{Tl}^{1+} \) state is more stable due to its electronic configuration. Thus, statement (A) is correct.
2. Statement (B): \( \text{Al}^{3+} \) does not get reduced easily
   The \( \text{Al}^{3+} \) ion is chemically stable as it has a noble gas electron configuration. It is not easily reduced because reducing it requires energy to add electrons to fill the higher energy orbitals. Therefore, statement (B) is correct.
3. Statement (C): Both \( \text{Al}^{3+} \) and \( \text{Tl}^{3+} \) are very stable in solution
   While \( \text{Al}^{3+} \) is stable, \( \text{Tl}^{3+} \) is not very stable in solution due to its tendency to reduce to the more stable \( \text{Tl}^{+} \) state. Hence, statement (C) is incorrect.
4. Statement (D): \( \text{Tl}^{+} \) is more stable than \( \text{Tl}^{3+} \)
   This is true because \( \text{Tl}^{+} \) has a half-filled \( 6s \) orbital which provides extra stability. Thus, statement (D) is correct.
5. Statement (E): \( \text{Al}^{3+} \) and \( \text{Tl}^{+} \) are highly stable
   As explained earlier, both \( \text{Al}^{3+} \) and \( \text{Tl}^{+} \) are stable due to their electronic configurations, making statement (E) correct.

Based on the analysis, the set of correct statements is (A), (B), (D), and (E).

Answer 2

Solution:

In this problem, we need to evaluate the stability and properties of different oxidation states of aluminum ($Al$) and thallium ($Tl$). Let's analyze each statement:

• (A) $Tl^{3+}$ is a powerful oxidizing agent: This is true. Thallium in the +3 oxidation state is known to be a strong oxidizing agent because it can readily gain electrons to get reduced to $Tl^+$, which is more stable.
• (B) $Al^{3+}$ does not get reduced easily: This is true. Aluminum in the +3 state forms a very stable ion and does not easily gain electrons to get reduced.
• (C) Both $Al^{3+}$ and $Tl^{3+}$ are very stable in solution: This statement is incorrect. Thallium($Tl$) in the +3 state is not very stable and tends to get reduced to the more stable +1 state ($Tl^+$).
• (D) $Tl^+$ is more stable than $Tl^{3+}$: This is true. The +1 oxidation state is more stable for thallium due to the inert pair effect.
• (E) $Al^{3+}$ and $Tl^+$ are highly stable: This is true. Aluminum in the +3 state and Thallium in the +1 state are both stable in solution.

Conclusion:
Upon analyzing the statements, the correct ones are (A), (B), (D), and (E). Therefore, the correct answer is:

(A), (B), (D) and (E) only