The correct statements from the following are: (A) Tl³⁺$\text{Tl}^{3+}$ is a powerful oxidising agent (B) Al³⁺$\text{Al}^{3+}$ does not get reduced easily (C) Both Al³⁺$\text{Al}^{3+}$ and Tl³⁺$\text{Tl}^{3+}$ are very stable in solution (D) Tl⁺$\text{Tl}^{+}$ is more stable than Tl³⁺$\text{Tl}^{3+}$ (E) Al³⁺$\text{Al}^{3+}$ and Tl⁺$\text{Tl}^{+}$ are highly stable Choose the correct answer from the options given below:

Related Formula

Core Logic

Let's analyze the group 13 stability dynamics:

• Inert Pair Effect: Down Group 13, the reluctance of inner ns²$ns^2$ electrons to participate in bonding increases. Thus, for Thallium (Tl), the +1$+1$ oxidation state is significantly more stable than the +3$+3$ oxidation state (Tl^+ > Tl³⁺$\text{Tl}^+ > \text{Tl}^{3+}$). This validates statement (D). [cite: 1020, 1032]
• Because Tl³⁺$\text{Tl}^{3+}$ is highly unstable, it eagerly captures two electrons to reduce to Tl^+$\text{Tl}^+$, acting as a powerful oxidizing agent, verifying statement (A). [cite: 1020, 1023]
• Aluminum is small and highly electropositive. Its standard reduction potential is heavily negative (E⁰ = -1.66 V$E^0 = -1.66\text{ V}$), meaning Al³⁺$\text{Al}^{3+}$ resists reduction and remains highly stable in solution, validating statements (B) and (E). [cite: 1026, 1027, 1038]

Step 1: Eliminating Flawed Entries

Statement (C) states that both are highly stable in solution, which is false since Tl³⁺$\text{Tl}^{3+}$ is highly unstable and readily oxidizes surrounding species. Thus, the valid statements are (A), (B), (D), and (E) only.

Pattern Recognition

Inert pair shortcuts: For heavy p-block blocks (like Tl, Pb, Bi$\text{Tl, Pb, Bi}$), the lowest oxidation state (+1, +2, +3$+1, +2, +3$ respectively) is always favored over the maximum group valence. Consequently, their high-valence ions act as excellent oxidizers.

Chapter Mix

Class 11 Chemistry: The p-Block Elements