JEE MainChemistryp Block Elements (Group 13 & 14)
Consider the following statements regarding the chemical behavior of Group 13 elements: (A) TlCl₃ acts as a strong oxidizing agent because the +1 oxidation state of Thallium is more stable than its +3 state. (B) The first ionization enthalpy of Gallium is higher than that of Aluminium. (C) Aluminium exhibits amphoteric character, dissolving in both dilute HCl and aqueous NaOH to liberate H₂ gas. (D) The Lewis acid st
Options
- A(A), (C) and (D) only
- B(B) and (C) only
- C(A), (B), (C) and (D)
- D(A), (B) and (C) only
Correct answer
D. (A), (B) and (C) only
Step-by-step solution
Statement (A) is correct. Due to the strong inert pair effect in Thallium, the +1 oxidation state is much more stable than the +3 state. Therefore, Tl ³⁺ readily accepts two electrons to become Tl ⁺ , making TlCl₃ a strong oxidizing agent. Statement (B) is correct. The first ionization enthalpy of Gallium is slightly higher than that of Aluminium. This anomaly arises because the poor shielding by the 3 d electrons in Gallium leads to a higher effective nuclear charge, which holds the valence electrons more tightly.