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

Step 1: Analyze each statement based on the properties of Aluminum and Thallium.
(A) \( Tl^{3+} \) is a powerful oxidising agent: Thallium belongs to Group 13. Its common oxidation states are +1 and +3. Due to the inert pair effect, the +1 oxidation state is more stable than the +3 oxidation state for heavier elements like Thallium. \( Tl^{3+} \) readily undergoes reduction to the more stable \( Tl^+ \) state, making it a strong oxidizing agent (it readily accepts electrons). This statement is correct. (B) \( Al^{3+} \) does not get reduced easily: Aluminum also belongs to Group 13. Its most stable oxidation state is +3. Due to its small size and high charge density, \( Al^{3+} \) has a high polarizing power and forms strong ionic bonds. Reducing \( Al^{3+} \) would involve a significant energy input to overcome these stable bonds and the stable electronic configuration. Therefore, \( Al^{3+} \) is very stable and not easily reduced. This statement is correct. (C) Both \( Al^{3+} \) and \( Tl^{3+} \) are very stable in solution: As discussed in (A), \( Tl^{3+} \) is unstable in solution as it readily reduces to \( Tl^+ \). \( Al^{3+} \) is stable in solution. Therefore, this statement is incorrect. (D) \( Tl^+ \) is more stable than \( Tl^{3+} \): Due to the inert pair effect, the \( ns^2 \) electrons in the valence shell of heavier p-block elements like Thallium tend to remain paired and are reluctant to participate in bonding. This makes the +1 oxidation state (where these \( ns^2 \) electrons are not involved in bonding) more stable than the +3 oxidation state (where these electrons are involved). This statement is correct. (E) \( Al^{3+} \) and \( Tl^+ \) are highly stable: \( Al^{3+} \) is the stable oxidation state for Aluminum due to its electronic configuration and bonding characteristics. \( Tl^+ \) is the more stable oxidation state for Thallium due to the inert pair effect. Therefore, both \( Al^{3+} \) and \( Tl^+ \) are highly stable in their respective contexts. This statement is correct.
Step 2: Identify the correct statements.
The correct statements are (A), (B), (D), and (E).
Step 3: Choose the option containing the correct statements.
The option containing statements (A), (B), (D), and (E) is (2).